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postgres/src/backend/parser/parse_clause.c
Bruce Momjian 7559d8ebfa Update copyrights for 2020 
Backpatch-through: update all files in master, backpatch legal files through 9.4
2020-01-01 12:21:45 -05:00

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/*-------------------------------------------------------------------------
*
* parse_clause.c
* handle clauses in parser
*
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/parser/parse_clause.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "access/nbtree.h"
#include "access/table.h"
#include "access/tsmapi.h"
#include "catalog/catalog.h"
#include "catalog/heap.h"
#include "catalog/pg_am.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/optimizer.h"
#include "parser/analyze.h"
#include "parser/parse_clause.h"
#include "parser/parse_coerce.h"
#include "parser/parse_collate.h"
#include "parser/parse_expr.h"
#include "parser/parse_func.h"
#include "parser/parse_oper.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "parser/parser.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteManip.h"
#include "utils/builtins.h"
#include "utils/catcache.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
/* Convenience macro for the most common makeNamespaceItem() case */
#define makeDefaultNSItem(rte, rti) \
makeNamespaceItem(rte, rti, true, true, false, true)
static void extractRemainingColumns(List *common_colnames,
List *src_colnames, List *src_colvars,
List **res_colnames, List **res_colvars);
static Node *transformJoinUsingClause(ParseState *pstate,
RangeTblEntry *leftRTE, RangeTblEntry *rightRTE,
List *leftVars, List *rightVars);
static Node *transformJoinOnClause(ParseState *pstate, JoinExpr *j,
List *namespace);
static RangeTblEntry *getRTEForSpecialRelationTypes(ParseState *pstate,
RangeVar *rv);
static RangeTblEntry *transformTableEntry(ParseState *pstate, RangeVar *r);
static RangeTblEntry *transformRangeSubselect(ParseState *pstate,
RangeSubselect *r);
static RangeTblEntry *transformRangeFunction(ParseState *pstate,
RangeFunction *r);
static RangeTblEntry *transformRangeTableFunc(ParseState *pstate,
RangeTableFunc *t);
static TableSampleClause *transformRangeTableSample(ParseState *pstate,
RangeTableSample *rts);
static Node *transformFromClauseItem(ParseState *pstate, Node *n,
RangeTblEntry **top_rte, int *top_rti,
List **namespace);
static Node *buildMergedJoinVar(ParseState *pstate, JoinType jointype,
Var *l_colvar, Var *r_colvar);
static ParseNamespaceItem *makeNamespaceItem(RangeTblEntry *rte, int rtindex,
bool rel_visible, bool cols_visible,
bool lateral_only, bool lateral_ok);
static void setNamespaceColumnVisibility(List *namespace, bool cols_visible);
static void setNamespaceLateralState(List *namespace,
bool lateral_only, bool lateral_ok);
static void checkExprIsVarFree(ParseState *pstate, Node *n,
const char *constructName);
static TargetEntry *findTargetlistEntrySQL92(ParseState *pstate, Node *node,
List **tlist, ParseExprKind exprKind);
static TargetEntry *findTargetlistEntrySQL99(ParseState *pstate, Node *node,
List **tlist, ParseExprKind exprKind);
static int get_matching_location(int sortgroupref,
List *sortgrouprefs, List *exprs);
static List *resolve_unique_index_expr(ParseState *pstate, InferClause *infer,
Relation heapRel);
static List *addTargetToGroupList(ParseState *pstate, TargetEntry *tle,
List *grouplist, List *targetlist, int location);
static WindowClause *findWindowClause(List *wclist, const char *name);
static Node *transformFrameOffset(ParseState *pstate, int frameOptions,
Oid rangeopfamily, Oid rangeopcintype, Oid *inRangeFunc,
Node *clause);
/*
* transformFromClause -
* Process the FROM clause and add items to the query's range table,
* joinlist, and namespace.
*
* Note: we assume that the pstate's p_rtable, p_joinlist, and p_namespace
* lists were initialized to NIL when the pstate was created.
* We will add onto any entries already present --- this is needed for rule
* processing, as well as for UPDATE and DELETE.
*/
void
transformFromClause(ParseState *pstate, List *frmList)
{
ListCell *fl;
/*
* The grammar will have produced a list of RangeVars, RangeSubselects,
* RangeFunctions, and/or JoinExprs. Transform each one (possibly adding
* entries to the rtable), check for duplicate refnames, and then add it
* to the joinlist and namespace.
*
* Note we must process the items left-to-right for proper handling of
* LATERAL references.
*/
foreach(fl, frmList)
{
Node *n = lfirst(fl);
RangeTblEntry *rte;
int rtindex;
List *namespace;
n = transformFromClauseItem(pstate, n,
&rte,
&rtindex,
&namespace);
checkNameSpaceConflicts(pstate, pstate->p_namespace, namespace);
/* Mark the new namespace items as visible only to LATERAL */
setNamespaceLateralState(namespace, true, true);
pstate->p_joinlist = lappend(pstate->p_joinlist, n);
pstate->p_namespace = list_concat(pstate->p_namespace, namespace);
}
/*
* We're done parsing the FROM list, so make all namespace items
* unconditionally visible. Note that this will also reset lateral_only
* for any namespace items that were already present when we were called;
* but those should have been that way already.
*/
setNamespaceLateralState(pstate->p_namespace, false, true);
}
/*
* setTargetTable
* Add the target relation of INSERT/UPDATE/DELETE to the range table,
* and make the special links to it in the ParseState.
*
* We also open the target relation and acquire a write lock on it.
* This must be done before processing the FROM list, in case the target
* is also mentioned as a source relation --- we want to be sure to grab
* the write lock before any read lock.
*
* If alsoSource is true, add the target to the query's joinlist and
* namespace. For INSERT, we don't want the target to be joined to;
* it's a destination of tuples, not a source. For UPDATE/DELETE,
* we do need to scan or join the target. (NOTE: we do not bother
* to check for namespace conflict; we assume that the namespace was
* initially empty in these cases.)
*
* Finally, we mark the relation as requiring the permissions specified
* by requiredPerms.
*
* Returns the rangetable index of the target relation.
*/
int
setTargetTable(ParseState *pstate, RangeVar *relation,
bool inh, bool alsoSource, AclMode requiredPerms)
{
RangeTblEntry *rte;
int rtindex;
/*
* ENRs hide tables of the same name, so we need to check for them first.
* In contrast, CTEs don't hide tables (for this purpose).
*/
if (relation->schemaname == NULL &&
scanNameSpaceForENR(pstate, relation->relname))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("relation \"%s\" cannot be the target of a modifying statement",
relation->relname)));
/* Close old target; this could only happen for multi-action rules */
if (pstate->p_target_relation != NULL)
table_close(pstate->p_target_relation, NoLock);
/*
* Open target rel and grab suitable lock (which we will hold till end of
* transaction).
*
* free_parsestate() will eventually do the corresponding table_close(),
* but *not* release the lock.
*/
pstate->p_target_relation = parserOpenTable(pstate, relation,
RowExclusiveLock);
/*
* Now build an RTE.
*/
rte = addRangeTableEntryForRelation(pstate, pstate->p_target_relation,
RowExclusiveLock,
relation->alias, inh, false);
/* assume new rte is at end */
rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
/* remember the RTE as being the query target */
pstate->p_target_rangetblentry = rte;
pstate->p_target_rtindex = rtindex;
/*
* Override addRangeTableEntry's default ACL_SELECT permissions check, and
* instead mark target table as requiring exactly the specified
* permissions.
*
* If we find an explicit reference to the rel later during parse
* analysis, we will add the ACL_SELECT bit back again; see
* markVarForSelectPriv and its callers.
*/
rte->requiredPerms = requiredPerms;
/*
* If UPDATE/DELETE, add table to joinlist and namespace.
*
* Note: some callers know that they can find the new ParseNamespaceItem
* at the end of the pstate->p_namespace list. This is a bit ugly but not
* worth complicating this function's signature for.
*/
if (alsoSource)
addRTEtoQuery(pstate, rte, true, true, true);
return rtindex;
}
/*
* Extract all not-in-common columns from column lists of a source table
*/
static void
extractRemainingColumns(List *common_colnames,
List *src_colnames, List *src_colvars,
List **res_colnames, List **res_colvars)
{
List *new_colnames = NIL;
List *new_colvars = NIL;
ListCell *lnames,
*lvars;
Assert(list_length(src_colnames) == list_length(src_colvars));
forboth(lnames, src_colnames, lvars, src_colvars)
{
char *colname = strVal(lfirst(lnames));
bool match = false;
ListCell *cnames;
foreach(cnames, common_colnames)
{
char *ccolname = strVal(lfirst(cnames));
if (strcmp(colname, ccolname) == 0)
{
match = true;
break;
}
}
if (!match)
{
new_colnames = lappend(new_colnames, lfirst(lnames));
new_colvars = lappend(new_colvars, lfirst(lvars));
}
}
*res_colnames = new_colnames;
*res_colvars = new_colvars;
}
/* transformJoinUsingClause()
* Build a complete ON clause from a partially-transformed USING list.
* We are given lists of nodes representing left and right match columns.
* Result is a transformed qualification expression.
*/
static Node *
transformJoinUsingClause(ParseState *pstate,
RangeTblEntry *leftRTE, RangeTblEntry *rightRTE,
List *leftVars, List *rightVars)
{
Node *result;
List *andargs = NIL;
ListCell *lvars,
*rvars;
/*
* We cheat a little bit here by building an untransformed operator tree
* whose leaves are the already-transformed Vars. This requires collusion
* from transformExpr(), which normally could be expected to complain
* about already-transformed subnodes. However, this does mean that we
* have to mark the columns as requiring SELECT privilege for ourselves;
* transformExpr() won't do it.
*/
forboth(lvars, leftVars, rvars, rightVars)
{
Var *lvar = (Var *) lfirst(lvars);
Var *rvar = (Var *) lfirst(rvars);
A_Expr *e;
/* Require read access to the join variables */
markVarForSelectPriv(pstate, lvar, leftRTE);
markVarForSelectPriv(pstate, rvar, rightRTE);
/* Now create the lvar = rvar join condition */
e = makeSimpleA_Expr(AEXPR_OP, "=",
(Node *) copyObject(lvar), (Node *) copyObject(rvar),
-1);
/* Prepare to combine into an AND clause, if multiple join columns */
andargs = lappend(andargs, e);
}
/* Only need an AND if there's more than one join column */
if (list_length(andargs) == 1)
result = (Node *) linitial(andargs);
else
result = (Node *) makeBoolExpr(AND_EXPR, andargs, -1);
/*
* Since the references are already Vars, and are certainly from the input
* relations, we don't have to go through the same pushups that
* transformJoinOnClause() does. Just invoke transformExpr() to fix up
* the operators, and we're done.
*/
result = transformExpr(pstate, result, EXPR_KIND_JOIN_USING);
result = coerce_to_boolean(pstate, result, "JOIN/USING");
return result;
}
/* transformJoinOnClause()
* Transform the qual conditions for JOIN/ON.
* Result is a transformed qualification expression.
*/
static Node *
transformJoinOnClause(ParseState *pstate, JoinExpr *j, List *namespace)
{
Node *result;
List *save_namespace;
/*
* The namespace that the join expression should see is just the two
* subtrees of the JOIN plus any outer references from upper pstate
* levels. Temporarily set this pstate's namespace accordingly. (We need
* not check for refname conflicts, because transformFromClauseItem()
* already did.) All namespace items are marked visible regardless of
* LATERAL state.
*/
setNamespaceLateralState(namespace, false, true);
save_namespace = pstate->p_namespace;
pstate->p_namespace = namespace;
result = transformWhereClause(pstate, j->quals,
EXPR_KIND_JOIN_ON, "JOIN/ON");
pstate->p_namespace = save_namespace;
return result;
}
/*
* transformTableEntry --- transform a RangeVar (simple relation reference)
*/
static RangeTblEntry *
transformTableEntry(ParseState *pstate, RangeVar *r)
{
RangeTblEntry *rte;
/* We need only build a range table entry */
rte = addRangeTableEntry(pstate, r, r->alias, r->inh, true);
return rte;
}
/*
* transformRangeSubselect --- transform a sub-SELECT appearing in FROM
*/
static RangeTblEntry *
transformRangeSubselect(ParseState *pstate, RangeSubselect *r)
{
Query *query;
RangeTblEntry *rte;
/*
* We require user to supply an alias for a subselect, per SQL92. To relax
* this, we'd have to be prepared to gin up a unique alias for an
* unlabeled subselect. (This is just elog, not ereport, because the
* grammar should have enforced it already. It'd probably be better to
* report the error here, but we don't have a good error location here.)
*/
if (r->alias == NULL)
elog(ERROR, "subquery in FROM must have an alias");
/*
* Set p_expr_kind to show this parse level is recursing to a subselect.
* We can't be nested within any expression, so don't need save-restore
* logic here.
*/
Assert(pstate->p_expr_kind == EXPR_KIND_NONE);
pstate->p_expr_kind = EXPR_KIND_FROM_SUBSELECT;
/*
* If the subselect is LATERAL, make lateral_only names of this level
* visible to it. (LATERAL can't nest within a single pstate level, so we
* don't need save/restore logic here.)
*/
Assert(!pstate->p_lateral_active);
pstate->p_lateral_active = r->lateral;
/*
* Analyze and transform the subquery.
*/
query = parse_sub_analyze(r->subquery, pstate, NULL,
isLockedRefname(pstate, r->alias->aliasname),
true);
/* Restore state */
pstate->p_lateral_active = false;
pstate->p_expr_kind = EXPR_KIND_NONE;
/*
* Check that we got a SELECT. Anything else should be impossible given
* restrictions of the grammar, but check anyway.
*/
if (!IsA(query, Query) ||
query->commandType != CMD_SELECT)
elog(ERROR, "unexpected non-SELECT command in subquery in FROM");
/*
* OK, build an RTE for the subquery.
*/
rte = addRangeTableEntryForSubquery(pstate,
query,
r->alias,
r->lateral,
true);
return rte;
}
/*
* transformRangeFunction --- transform a function call appearing in FROM
*/
static RangeTblEntry *
transformRangeFunction(ParseState *pstate, RangeFunction *r)
{
List *funcexprs = NIL;
List *funcnames = NIL;
List *coldeflists = NIL;
bool is_lateral;
RangeTblEntry *rte;
ListCell *lc;
/*
* We make lateral_only names of this level visible, whether or not the
* RangeFunction is explicitly marked LATERAL. This is needed for SQL
* spec compliance in the case of UNNEST(), and seems useful on
* convenience grounds for all functions in FROM.
*
* (LATERAL can't nest within a single pstate level, so we don't need
* save/restore logic here.)
*/
Assert(!pstate->p_lateral_active);
pstate->p_lateral_active = true;
/*
* Transform the raw expressions.
*
* While transforming, also save function names for possible use as alias
* and column names. We use the same transformation rules as for a SELECT
* output expression. For a FuncCall node, the result will be the
* function name, but it is possible for the grammar to hand back other
* node types.
*
* We have to get this info now, because FigureColname only works on raw
* parsetrees. Actually deciding what to do with the names is left up to
* addRangeTableEntryForFunction.
*
* Likewise, collect column definition lists if there were any. But
* complain if we find one here and the RangeFunction has one too.
*/
foreach(lc, r->functions)
{
List *pair = (List *) lfirst(lc);
Node *fexpr;
List *coldeflist;
Node *newfexpr;
Node *last_srf;
/* Disassemble the function-call/column-def-list pairs */
Assert(list_length(pair) == 2);
fexpr = (Node *) linitial(pair);
coldeflist = (List *) lsecond(pair);
/*
* If we find a function call unnest() with more than one argument and
* no special decoration, transform it into separate unnest() calls on
* each argument. This is a kluge, for sure, but it's less nasty than
* other ways of implementing the SQL-standard UNNEST() syntax.
*
* If there is any decoration (including a coldeflist), we don't
* transform, which probably means a no-such-function error later. We
* could alternatively throw an error right now, but that doesn't seem
* tremendously helpful. If someone is using any such decoration,
* then they're not using the SQL-standard syntax, and they're more
* likely expecting an un-tweaked function call.
*
* Note: the transformation changes a non-schema-qualified unnest()
* function name into schema-qualified pg_catalog.unnest(). This
* choice is also a bit debatable, but it seems reasonable to force
* use of built-in unnest() when we make this transformation.
*/
if (IsA(fexpr, FuncCall))
{
FuncCall *fc = (FuncCall *) fexpr;
if (list_length(fc->funcname) == 1 &&
strcmp(strVal(linitial(fc->funcname)), "unnest") == 0 &&
list_length(fc->args) > 1 &&
fc->agg_order == NIL &&
fc->agg_filter == NULL &&
!fc->agg_star &&
!fc->agg_distinct &&
!fc->func_variadic &&
fc->over == NULL &&
coldeflist == NIL)
{
ListCell *lc;
foreach(lc, fc->args)
{
Node *arg = (Node *) lfirst(lc);
FuncCall *newfc;
last_srf = pstate->p_last_srf;
newfc = makeFuncCall(SystemFuncName("unnest"),
list_make1(arg),
fc->location);
newfexpr = transformExpr(pstate, (Node *) newfc,
EXPR_KIND_FROM_FUNCTION);
/* nodeFunctionscan.c requires SRFs to be at top level */
if (pstate->p_last_srf != last_srf &&
pstate->p_last_srf != newfexpr)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-returning functions must appear at top level of FROM"),
parser_errposition(pstate,
exprLocation(pstate->p_last_srf))));
funcexprs = lappend(funcexprs, newfexpr);
funcnames = lappend(funcnames,
FigureColname((Node *) newfc));
/* coldeflist is empty, so no error is possible */
coldeflists = lappend(coldeflists, coldeflist);
}
continue; /* done with this function item */
}
}
/* normal case ... */
last_srf = pstate->p_last_srf;
newfexpr = transformExpr(pstate, fexpr,
EXPR_KIND_FROM_FUNCTION);
/* nodeFunctionscan.c requires SRFs to be at top level */
if (pstate->p_last_srf != last_srf &&
pstate->p_last_srf != newfexpr)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-returning functions must appear at top level of FROM"),
parser_errposition(pstate,
exprLocation(pstate->p_last_srf))));
funcexprs = lappend(funcexprs, newfexpr);
funcnames = lappend(funcnames,
FigureColname(fexpr));
if (coldeflist && r->coldeflist)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("multiple column definition lists are not allowed for the same function"),
parser_errposition(pstate,
exprLocation((Node *) r->coldeflist))));
coldeflists = lappend(coldeflists, coldeflist);
}
pstate->p_lateral_active = false;
/*
* We must assign collations now so that the RTE exposes correct collation
* info for Vars created from it.
*/
assign_list_collations(pstate, funcexprs);
/*
* Install the top-level coldeflist if there was one (we already checked
* that there was no conflicting per-function coldeflist).
*
* We only allow this when there's a single function (even after UNNEST
* expansion) and no WITH ORDINALITY. The reason for the latter
* restriction is that it's not real clear whether the ordinality column
* should be in the coldeflist, and users are too likely to make mistakes
* in one direction or the other. Putting the coldeflist inside ROWS
* FROM() is much clearer in this case.
*/
if (r->coldeflist)
{
if (list_length(funcexprs) != 1)
{
if (r->is_rowsfrom)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("ROWS FROM() with multiple functions cannot have a column definition list"),
errhint("Put a separate column definition list for each function inside ROWS FROM()."),
parser_errposition(pstate,
exprLocation((Node *) r->coldeflist))));
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("UNNEST() with multiple arguments cannot have a column definition list"),
errhint("Use separate UNNEST() calls inside ROWS FROM(), and attach a column definition list to each one."),
parser_errposition(pstate,
exprLocation((Node *) r->coldeflist))));
}
if (r->ordinality)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("WITH ORDINALITY cannot be used with a column definition list"),
errhint("Put the column definition list inside ROWS FROM()."),
parser_errposition(pstate,
exprLocation((Node *) r->coldeflist))));
coldeflists = list_make1(r->coldeflist);
}
/*
* Mark the RTE as LATERAL if the user said LATERAL explicitly, or if
* there are any lateral cross-references in it.
*/
is_lateral = r->lateral || contain_vars_of_level((Node *) funcexprs, 0);
/*
* OK, build an RTE for the function.
*/
rte = addRangeTableEntryForFunction(pstate,
funcnames, funcexprs, coldeflists,
r, is_lateral, true);
return rte;
}
/*
* transformRangeTableFunc -
* Transform a raw RangeTableFunc into TableFunc.
*
* Transform the namespace clauses, the document-generating expression, the
* row-generating expression, the column-generating expressions, and the
* default value expressions.
*/
static RangeTblEntry *
transformRangeTableFunc(ParseState *pstate, RangeTableFunc *rtf)
{
TableFunc *tf = makeNode(TableFunc);
const char *constructName;
Oid docType;
RangeTblEntry *rte;
bool is_lateral;
ListCell *col;
char **names;
int colno;
/* Currently only XMLTABLE is supported */
constructName = "XMLTABLE";
docType = XMLOID;
/*
* We make lateral_only names of this level visible, whether or not the
* RangeTableFunc is explicitly marked LATERAL. This is needed for SQL
* spec compliance and seems useful on convenience grounds for all
* functions in FROM.
*
* (LATERAL can't nest within a single pstate level, so we don't need
* save/restore logic here.)
*/
Assert(!pstate->p_lateral_active);
pstate->p_lateral_active = true;
/* Transform and apply typecast to the row-generating expression ... */
Assert(rtf->rowexpr != NULL);
tf->rowexpr = coerce_to_specific_type(pstate,
transformExpr(pstate, rtf->rowexpr, EXPR_KIND_FROM_FUNCTION),
TEXTOID,
constructName);
assign_expr_collations(pstate, tf->rowexpr);
/* ... and to the document itself */
Assert(rtf->docexpr != NULL);
tf->docexpr = coerce_to_specific_type(pstate,
transformExpr(pstate, rtf->docexpr, EXPR_KIND_FROM_FUNCTION),
docType,
constructName);
assign_expr_collations(pstate, tf->docexpr);
/* undef ordinality column number */
tf->ordinalitycol = -1;
/* Process column specs */
names = palloc(sizeof(char *) * list_length(rtf->columns));
colno = 0;
foreach(col, rtf->columns)
{
RangeTableFuncCol *rawc = (RangeTableFuncCol *) lfirst(col);
Oid typid;
int32 typmod;
Node *colexpr;
Node *coldefexpr;
int j;
tf->colnames = lappend(tf->colnames,
makeString(pstrdup(rawc->colname)));
/*
* Determine the type and typmod for the new column. FOR ORDINALITY
* columns are INTEGER per spec; the others are user-specified.
*/
if (rawc->for_ordinality)
{
if (tf->ordinalitycol != -1)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("only one FOR ORDINALITY column is allowed"),
parser_errposition(pstate, rawc->location)));
typid = INT4OID;
typmod = -1;
tf->ordinalitycol = colno;
}
else
{
if (rawc->typeName->setof)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column \"%s\" cannot be declared SETOF",
rawc->colname),
parser_errposition(pstate, rawc->location)));
typenameTypeIdAndMod(pstate, rawc->typeName,
&typid, &typmod);
}
tf->coltypes = lappend_oid(tf->coltypes, typid);
tf->coltypmods = lappend_int(tf->coltypmods, typmod);
tf->colcollations = lappend_oid(tf->colcollations,
get_typcollation(typid));
/* Transform the PATH and DEFAULT expressions */
if (rawc->colexpr)
{
colexpr = coerce_to_specific_type(pstate,
transformExpr(pstate, rawc->colexpr,
EXPR_KIND_FROM_FUNCTION),
TEXTOID,
constructName);
assign_expr_collations(pstate, colexpr);
}
else
colexpr = NULL;
if (rawc->coldefexpr)
{
coldefexpr = coerce_to_specific_type_typmod(pstate,
transformExpr(pstate, rawc->coldefexpr,
EXPR_KIND_FROM_FUNCTION),
typid, typmod,
constructName);
assign_expr_collations(pstate, coldefexpr);
}
else
coldefexpr = NULL;
tf->colexprs = lappend(tf->colexprs, colexpr);
tf->coldefexprs = lappend(tf->coldefexprs, coldefexpr);
if (rawc->is_not_null)
tf->notnulls = bms_add_member(tf->notnulls, colno);
/* make sure column names are unique */
for (j = 0; j < colno; j++)
if (strcmp(names[j], rawc->colname) == 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("column name \"%s\" is not unique",
rawc->colname),
parser_errposition(pstate, rawc->location)));
names[colno] = rawc->colname;
colno++;
}
pfree(names);
/* Namespaces, if any, also need to be transformed */
if (rtf->namespaces != NIL)
{
ListCell *ns;
ListCell *lc2;
List *ns_uris = NIL;
List *ns_names = NIL;
bool default_ns_seen = false;
foreach(ns, rtf->namespaces)
{
ResTarget *r = (ResTarget *) lfirst(ns);
Node *ns_uri;
Assert(IsA(r, ResTarget));
ns_uri = transformExpr(pstate, r->val, EXPR_KIND_FROM_FUNCTION);
ns_uri = coerce_to_specific_type(pstate, ns_uri,
TEXTOID, constructName);
assign_expr_collations(pstate, ns_uri);
ns_uris = lappend(ns_uris, ns_uri);
/* Verify consistency of name list: no dupes, only one DEFAULT */
if (r->name != NULL)
{
foreach(lc2, ns_names)
{
Value *ns_node = (Value *) lfirst(lc2);
if (ns_node == NULL)
continue;
if (strcmp(strVal(ns_node), r->name) == 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("namespace name \"%s\" is not unique",
r->name),
parser_errposition(pstate, r->location)));
}
}
else
{
if (default_ns_seen)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("only one default namespace is allowed"),
parser_errposition(pstate, r->location)));
default_ns_seen = true;
}
/* We represent DEFAULT by a null pointer */
ns_names = lappend(ns_names,
r->name ? makeString(r->name) : NULL);
}
tf->ns_uris = ns_uris;
tf->ns_names = ns_names;
}
tf->location = rtf->location;
pstate->p_lateral_active = false;
/*
* Mark the RTE as LATERAL if the user said LATERAL explicitly, or if
* there are any lateral cross-references in it.
*/
is_lateral = rtf->lateral || contain_vars_of_level((Node *) tf, 0);
rte = addRangeTableEntryForTableFunc(pstate,
tf, rtf->alias, is_lateral, true);
return rte;
}
/*
* transformRangeTableSample --- transform a TABLESAMPLE clause
*
* Caller has already transformed rts->relation, we just have to validate
* the remaining fields and create a TableSampleClause node.
*/
static TableSampleClause *
transformRangeTableSample(ParseState *pstate, RangeTableSample *rts)
{
TableSampleClause *tablesample;
Oid handlerOid;
Oid funcargtypes[1];
TsmRoutine *tsm;
List *fargs;
ListCell *larg,
*ltyp;
/*
* To validate the sample method name, look up the handler function, which
* has the same name, one dummy INTERNAL argument, and a result type of
* tsm_handler. (Note: tablesample method names are not schema-qualified
* in the SQL standard; but since they are just functions to us, we allow
* schema qualification to resolve any potential ambiguity.)
*/
funcargtypes[0] = INTERNALOID;
handlerOid = LookupFuncName(rts->method, 1, funcargtypes, true);
/* we want error to complain about no-such-method, not no-such-function */
if (!OidIsValid(handlerOid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablesample method %s does not exist",
NameListToString(rts->method)),
parser_errposition(pstate, rts->location)));
/* check that handler has correct return type */
if (get_func_rettype(handlerOid) != TSM_HANDLEROID)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("function %s must return type %s",
NameListToString(rts->method), "tsm_handler"),
parser_errposition(pstate, rts->location)));
/* OK, run the handler to get TsmRoutine, for argument type info */
tsm = GetTsmRoutine(handlerOid);
tablesample = makeNode(TableSampleClause);
tablesample->tsmhandler = handlerOid;
/* check user provided the expected number of arguments */
if (list_length(rts->args) != list_length(tsm->parameterTypes))
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLESAMPLE_ARGUMENT),
errmsg_plural("tablesample method %s requires %d argument, not %d",
"tablesample method %s requires %d arguments, not %d",
list_length(tsm->parameterTypes),
NameListToString(rts->method),
list_length(tsm->parameterTypes),
list_length(rts->args)),
parser_errposition(pstate, rts->location)));
/*
* Transform the arguments, typecasting them as needed. Note we must also
* assign collations now, because assign_query_collations() doesn't
* examine any substructure of RTEs.
*/
fargs = NIL;
forboth(larg, rts->args, ltyp, tsm->parameterTypes)
{
Node *arg = (Node *) lfirst(larg);
Oid argtype = lfirst_oid(ltyp);
arg = transformExpr(pstate, arg, EXPR_KIND_FROM_FUNCTION);
arg = coerce_to_specific_type(pstate, arg, argtype, "TABLESAMPLE");
assign_expr_collations(pstate, arg);
fargs = lappend(fargs, arg);
}
tablesample->args = fargs;
/* Process REPEATABLE (seed) */
if (rts->repeatable != NULL)
{
Node *arg;
if (!tsm->repeatable_across_queries)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("tablesample method %s does not support REPEATABLE",
NameListToString(rts->method)),
parser_errposition(pstate, rts->location)));
arg = transformExpr(pstate, rts->repeatable, EXPR_KIND_FROM_FUNCTION);
arg = coerce_to_specific_type(pstate, arg, FLOAT8OID, "REPEATABLE");
assign_expr_collations(pstate, arg);
tablesample->repeatable = (Expr *) arg;
}
else
tablesample->repeatable = NULL;
return tablesample;
}
/*
* getRTEForSpecialRelationTypes
*
* If given RangeVar refers to a CTE or an EphemeralNamedRelation,
* build and return an appropriate RTE, otherwise return NULL
*/
static RangeTblEntry *
getRTEForSpecialRelationTypes(ParseState *pstate, RangeVar *rv)
{
CommonTableExpr *cte;
Index levelsup;
RangeTblEntry *rte;
/*
* if it is a qualified name, it can't be a CTE or tuplestore reference
*/
if (rv->schemaname)
return NULL;
cte = scanNameSpaceForCTE(pstate, rv->relname, &levelsup);
if (cte)
rte = addRangeTableEntryForCTE(pstate, cte, levelsup, rv, true);
else if (scanNameSpaceForENR(pstate, rv->relname))
rte = addRangeTableEntryForENR(pstate, rv, true);
else
rte = NULL;
return rte;
}
/*
* transformFromClauseItem -
* Transform a FROM-clause item, adding any required entries to the
* range table list being built in the ParseState, and return the
* transformed item ready to include in the joinlist. Also build a
* ParseNamespaceItem list describing the names exposed by this item.
* This routine can recurse to handle SQL92 JOIN expressions.
*
* The function return value is the node to add to the jointree (a
* RangeTblRef or JoinExpr). Additional output parameters are:
*
* *top_rte: receives the RTE corresponding to the jointree item.
* (We could extract this from the function return node, but it saves cycles
* to pass it back separately.)
*
* *top_rti: receives the rangetable index of top_rte. (Ditto.)
*
* *namespace: receives a List of ParseNamespaceItems for the RTEs exposed
* as table/column names by this item. (The lateral_only flags in these items
* are indeterminate and should be explicitly set by the caller before use.)
*/
static Node *
transformFromClauseItem(ParseState *pstate, Node *n,
RangeTblEntry **top_rte, int *top_rti,
List **namespace)
{
if (IsA(n, RangeVar))
{
/* Plain relation reference, or perhaps a CTE reference */
RangeVar *rv = (RangeVar *) n;
RangeTblRef *rtr;
RangeTblEntry *rte;
int rtindex;
/* Check if it's a CTE or tuplestore reference */
rte = getRTEForSpecialRelationTypes(pstate, rv);
/* if not found above, must be a table reference */
if (!rte)
rte = transformTableEntry(pstate, rv);
/* assume new rte is at end */
rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
*top_rte = rte;
*top_rti = rtindex;
*namespace = list_make1(makeDefaultNSItem(rte, rtindex));
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
return (Node *) rtr;
}
else if (IsA(n, RangeSubselect))
{
/* sub-SELECT is like a plain relation */
RangeTblRef *rtr;
RangeTblEntry *rte;
int rtindex;
rte = transformRangeSubselect(pstate, (RangeSubselect *) n);
/* assume new rte is at end */
rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
*top_rte = rte;
*top_rti = rtindex;
*namespace = list_make1(makeDefaultNSItem(rte, rtindex));
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
return (Node *) rtr;
}
else if (IsA(n, RangeFunction))
{
/* function is like a plain relation */
RangeTblRef *rtr;
RangeTblEntry *rte;
int rtindex;
rte = transformRangeFunction(pstate, (RangeFunction *) n);
/* assume new rte is at end */
rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
*top_rte = rte;
*top_rti = rtindex;
*namespace = list_make1(makeDefaultNSItem(rte, rtindex));
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
return (Node *) rtr;
}
else if (IsA(n, RangeTableFunc))
{
/* table function is like a plain relation */
RangeTblRef *rtr;
RangeTblEntry *rte;
int rtindex;
rte = transformRangeTableFunc(pstate, (RangeTableFunc *) n);
/* assume new rte is at end */
rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
*top_rte = rte;
*top_rti = rtindex;
*namespace = list_make1(makeDefaultNSItem(rte, rtindex));
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
return (Node *) rtr;
}
else if (IsA(n, RangeTableSample))
{
/* TABLESAMPLE clause (wrapping some other valid FROM node) */
RangeTableSample *rts = (RangeTableSample *) n;
Node *rel;
RangeTblRef *rtr;
RangeTblEntry *rte;
/* Recursively transform the contained relation */
rel = transformFromClauseItem(pstate, rts->relation,
top_rte, top_rti, namespace);
/* Currently, grammar could only return a RangeVar as contained rel */
rtr = castNode(RangeTblRef, rel);
rte = rt_fetch(rtr->rtindex, pstate->p_rtable);
/* We only support this on plain relations and matviews */
if (rte->relkind != RELKIND_RELATION &&
rte->relkind != RELKIND_MATVIEW &&
rte->relkind != RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("TABLESAMPLE clause can only be applied to tables and materialized views"),
parser_errposition(pstate, exprLocation(rts->relation))));
/* Transform TABLESAMPLE details and attach to the RTE */
rte->tablesample = transformRangeTableSample(pstate, rts);
return (Node *) rtr;
}
else if (IsA(n, JoinExpr))
{
/* A newfangled join expression */
JoinExpr *j = (JoinExpr *) n;
RangeTblEntry *l_rte;
RangeTblEntry *r_rte;
int l_rtindex;
int r_rtindex;
List *l_namespace,
*r_namespace,
*my_namespace,
*l_colnames,
*r_colnames,
*res_colnames,
*l_colvars,
*r_colvars,
*res_colvars;
bool lateral_ok;
int sv_namespace_length;
RangeTblEntry *rte;
int k;
/*
* Recursively process the left subtree, then the right. We must do
* it in this order for correct visibility of LATERAL references.
*/
j->larg = transformFromClauseItem(pstate, j->larg,
&l_rte,
&l_rtindex,
&l_namespace);
/*
* Make the left-side RTEs available for LATERAL access within the
* right side, by temporarily adding them to the pstate's namespace
* list. Per SQL:2008, if the join type is not INNER or LEFT then the
* left-side names must still be exposed, but it's an error to
* reference them. (Stupid design, but that's what it says.) Hence,
* we always push them into the namespace, but mark them as not
* lateral_ok if the jointype is wrong.
*
* Notice that we don't require the merged namespace list to be
* conflict-free. See the comments for scanNameSpaceForRefname().
*/
lateral_ok = (j->jointype == JOIN_INNER || j->jointype == JOIN_LEFT);
setNamespaceLateralState(l_namespace, true, lateral_ok);
sv_namespace_length = list_length(pstate->p_namespace);
pstate->p_namespace = list_concat(pstate->p_namespace, l_namespace);
/* And now we can process the RHS */
j->rarg = transformFromClauseItem(pstate, j->rarg,
&r_rte,
&r_rtindex,
&r_namespace);
/* Remove the left-side RTEs from the namespace list again */
pstate->p_namespace = list_truncate(pstate->p_namespace,
sv_namespace_length);
/*
* Check for conflicting refnames in left and right subtrees. Must do
* this because higher levels will assume I hand back a self-
* consistent namespace list.
*/
checkNameSpaceConflicts(pstate, l_namespace, r_namespace);
/*
* Generate combined namespace info for possible use below.
*/
my_namespace = list_concat(l_namespace, r_namespace);
/*
* Extract column name and var lists from both subtrees
*
* Note: expandRTE returns new lists, safe for me to modify
*/
expandRTE(l_rte, l_rtindex, 0, -1, false,
&l_colnames, &l_colvars);
expandRTE(r_rte, r_rtindex, 0, -1, false,
&r_colnames, &r_colvars);
/*
* Natural join does not explicitly specify columns; must generate
* columns to join. Need to run through the list of columns from each
* table or join result and match up the column names. Use the first
* table, and check every column in the second table for a match.
* (We'll check that the matches were unique later on.) The result of
* this step is a list of column names just like an explicitly-written
* USING list.
*/
if (j->isNatural)
{
List *rlist = NIL;
ListCell *lx,
*rx;
Assert(j->usingClause == NIL); /* shouldn't have USING() too */
foreach(lx, l_colnames)
{
char *l_colname = strVal(lfirst(lx));
Value *m_name = NULL;
foreach(rx, r_colnames)
{
char *r_colname = strVal(lfirst(rx));
if (strcmp(l_colname, r_colname) == 0)
{
m_name = makeString(l_colname);
break;
}
}
/* matched a right column? then keep as join column... */
if (m_name != NULL)
rlist = lappend(rlist, m_name);
}
j->usingClause = rlist;
}
/*
* Now transform the join qualifications, if any.
*/
res_colnames = NIL;
res_colvars = NIL;
if (j->usingClause)
{
/*
* JOIN/USING (or NATURAL JOIN, as transformed above). Transform
* the list into an explicit ON-condition, and generate a list of
* merged result columns.
*/
List *ucols = j->usingClause;
List *l_usingvars = NIL;
List *r_usingvars = NIL;
ListCell *ucol;
Assert(j->quals == NULL); /* shouldn't have ON() too */
foreach(ucol, ucols)
{
char *u_colname = strVal(lfirst(ucol));
ListCell *col;
int ndx;
int l_index = -1;
int r_index = -1;
Var *l_colvar,
*r_colvar;
/* Check for USING(foo,foo) */
foreach(col, res_colnames)
{
char *res_colname = strVal(lfirst(col));
if (strcmp(res_colname, u_colname) == 0)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column name \"%s\" appears more than once in USING clause",
u_colname)));
}
/* Find it in left input */
ndx = 0;
foreach(col, l_colnames)
{
char *l_colname = strVal(lfirst(col));
if (strcmp(l_colname, u_colname) == 0)
{
if (l_index >= 0)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_COLUMN),
errmsg("common column name \"%s\" appears more than once in left table",
u_colname)));
l_index = ndx;
}
ndx++;
}
if (l_index < 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" specified in USING clause does not exist in left table",
u_colname)));
/* Find it in right input */
ndx = 0;
foreach(col, r_colnames)
{
char *r_colname = strVal(lfirst(col));
if (strcmp(r_colname, u_colname) == 0)
{
if (r_index >= 0)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_COLUMN),
errmsg("common column name \"%s\" appears more than once in right table",
u_colname)));
r_index = ndx;
}
ndx++;
}
if (r_index < 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" specified in USING clause does not exist in right table",
u_colname)));
l_colvar = list_nth(l_colvars, l_index);
l_usingvars = lappend(l_usingvars, l_colvar);
r_colvar = list_nth(r_colvars, r_index);
r_usingvars = lappend(r_usingvars, r_colvar);
res_colnames = lappend(res_colnames, lfirst(ucol));
res_colvars = lappend(res_colvars,
buildMergedJoinVar(pstate,
j->jointype,
l_colvar,
r_colvar));
}
j->quals = transformJoinUsingClause(pstate,
l_rte,
r_rte,
l_usingvars,
r_usingvars);
}
else if (j->quals)
{
/* User-written ON-condition; transform it */
j->quals = transformJoinOnClause(pstate, j, my_namespace);
}
else
{
/* CROSS JOIN: no quals */
}
/* Add remaining columns from each side to the output columns */
extractRemainingColumns(res_colnames,
l_colnames, l_colvars,
&l_colnames, &l_colvars);
extractRemainingColumns(res_colnames,
r_colnames, r_colvars,
&r_colnames, &r_colvars);
res_colnames = list_concat(res_colnames, l_colnames);
res_colvars = list_concat(res_colvars, l_colvars);
res_colnames = list_concat(res_colnames, r_colnames);
res_colvars = list_concat(res_colvars, r_colvars);
/*
* Check alias (AS clause), if any.
*/
if (j->alias)
{
if (j->alias->colnames != NIL)
{
if (list_length(j->alias->colnames) > list_length(res_colnames))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("column alias list for \"%s\" has too many entries",
j->alias->aliasname)));
}
}
/*
* Now build an RTE for the result of the join
*/
rte = addRangeTableEntryForJoin(pstate,
res_colnames,
j->jointype,
res_colvars,
j->alias,
true);
/* assume new rte is at end */
j->rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(j->rtindex, pstate->p_rtable));
*top_rte = rte;
*top_rti = j->rtindex;
/* make a matching link to the JoinExpr for later use */
for (k = list_length(pstate->p_joinexprs) + 1; k < j->rtindex; k++)
pstate->p_joinexprs = lappend(pstate->p_joinexprs, NULL);
pstate->p_joinexprs = lappend(pstate->p_joinexprs, j);
Assert(list_length(pstate->p_joinexprs) == j->rtindex);
/*
* Prepare returned namespace list. If the JOIN has an alias then it
* hides the contained RTEs completely; otherwise, the contained RTEs
* are still visible as table names, but are not visible for
* unqualified column-name access.
*
* Note: if there are nested alias-less JOINs, the lower-level ones
* will remain in the list although they have neither p_rel_visible
* nor p_cols_visible set. We could delete such list items, but it's
* unclear that it's worth expending cycles to do so.
*/
if (j->alias != NULL)
my_namespace = NIL;
else
setNamespaceColumnVisibility(my_namespace, false);
/*
* The join RTE itself is always made visible for unqualified column
* names. It's visible as a relation name only if it has an alias.
*/
*namespace = lappend(my_namespace,
makeNamespaceItem(rte,
j->rtindex,
(j->alias != NULL),
true,
false,
true));
return (Node *) j;
}
else
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(n));
return NULL; /* can't get here, keep compiler quiet */
}
/*
* buildMergedJoinVar -
* generate a suitable replacement expression for a merged join column
*/
static Node *
buildMergedJoinVar(ParseState *pstate, JoinType jointype,
Var *l_colvar, Var *r_colvar)
{
Oid outcoltype;
int32 outcoltypmod;
Node *l_node,
*r_node,
*res_node;
/*
* Choose output type if input types are dissimilar.
*/
outcoltype = l_colvar->vartype;
outcoltypmod = l_colvar->vartypmod;
if (outcoltype != r_colvar->vartype)
{
outcoltype = select_common_type(pstate,
list_make2(l_colvar, r_colvar),
"JOIN/USING",
NULL);
outcoltypmod = -1; /* ie, unknown */
}
else if (outcoltypmod != r_colvar->vartypmod)
{
/* same type, but not same typmod */
outcoltypmod = -1; /* ie, unknown */
}
/*
* Insert coercion functions if needed. Note that a difference in typmod
* can only happen if input has typmod but outcoltypmod is -1. In that
* case we insert a RelabelType to clearly mark that result's typmod is
* not same as input. We never need coerce_type_typmod.
*/
if (l_colvar->vartype != outcoltype)
l_node = coerce_type(pstate, (Node *) l_colvar, l_colvar->vartype,
outcoltype, outcoltypmod,
COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1);
else if (l_colvar->vartypmod != outcoltypmod)
l_node = (Node *) makeRelabelType((Expr *) l_colvar,
outcoltype, outcoltypmod,
InvalidOid, /* fixed below */
COERCE_IMPLICIT_CAST);
else
l_node = (Node *) l_colvar;
if (r_colvar->vartype != outcoltype)
r_node = coerce_type(pstate, (Node *) r_colvar, r_colvar->vartype,
outcoltype, outcoltypmod,
COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1);
else if (r_colvar->vartypmod != outcoltypmod)
r_node = (Node *) makeRelabelType((Expr *) r_colvar,
outcoltype, outcoltypmod,
InvalidOid, /* fixed below */
COERCE_IMPLICIT_CAST);
else
r_node = (Node *) r_colvar;
/*
* Choose what to emit
*/
switch (jointype)
{
case JOIN_INNER:
/*
* We can use either var; prefer non-coerced one if available.
*/
if (IsA(l_node, Var))
res_node = l_node;
else if (IsA(r_node, Var))
res_node = r_node;
else
res_node = l_node;
break;
case JOIN_LEFT:
/* Always use left var */
res_node = l_node;
break;
case JOIN_RIGHT:
/* Always use right var */
res_node = r_node;
break;
case JOIN_FULL:
{
/*
* Here we must build a COALESCE expression to ensure that the
* join output is non-null if either input is.
*/
CoalesceExpr *c = makeNode(CoalesceExpr);
c->coalescetype = outcoltype;
/* coalescecollid will get set below */
c->args = list_make2(l_node, r_node);
c->location = -1;
res_node = (Node *) c;
break;
}
default:
elog(ERROR, "unrecognized join type: %d", (int) jointype);
res_node = NULL; /* keep compiler quiet */
break;
}
/*
* Apply assign_expr_collations to fix up the collation info in the
* coercion and CoalesceExpr nodes, if we made any. This must be done now
* so that the join node's alias vars show correct collation info.
*/
assign_expr_collations(pstate, res_node);
return res_node;
}
/*
* makeNamespaceItem -
* Convenience subroutine to construct a ParseNamespaceItem.
*/
static ParseNamespaceItem *
makeNamespaceItem(RangeTblEntry *rte, int rtindex,
bool rel_visible, bool cols_visible,
bool lateral_only, bool lateral_ok)
{
ParseNamespaceItem *nsitem;
nsitem = (ParseNamespaceItem *) palloc(sizeof(ParseNamespaceItem));
nsitem->p_rte = rte;
nsitem->p_rtindex = rtindex;
nsitem->p_rel_visible = rel_visible;
nsitem->p_cols_visible = cols_visible;
nsitem->p_lateral_only = lateral_only;
nsitem->p_lateral_ok = lateral_ok;
return nsitem;
}
/*
* setNamespaceColumnVisibility -
* Convenience subroutine to update cols_visible flags in a namespace list.
*/
static void
setNamespaceColumnVisibility(List *namespace, bool cols_visible)
{
ListCell *lc;
foreach(lc, namespace)
{
ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(lc);
nsitem->p_cols_visible = cols_visible;
}
}
/*
* setNamespaceLateralState -
* Convenience subroutine to update LATERAL flags in a namespace list.
*/
static void
setNamespaceLateralState(List *namespace, bool lateral_only, bool lateral_ok)
{
ListCell *lc;
foreach(lc, namespace)
{
ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(lc);
nsitem->p_lateral_only = lateral_only;
nsitem->p_lateral_ok = lateral_ok;
}
}
/*
* transformWhereClause -
* Transform the qualification and make sure it is of type boolean.
* Used for WHERE and allied clauses.
*
* constructName does not affect the semantics, but is used in error messages
*/
Node *
transformWhereClause(ParseState *pstate, Node *clause,
ParseExprKind exprKind, const char *constructName)
{
Node *qual;
if (clause == NULL)
return NULL;
qual = transformExpr(pstate, clause, exprKind);
qual = coerce_to_boolean(pstate, qual, constructName);
return qual;
}
/*
* transformLimitClause -
* Transform the expression and make sure it is of type bigint.
* Used for LIMIT and allied clauses.
*
* Note: as of Postgres 8.2, LIMIT expressions are expected to yield int8,
* rather than int4 as before.
*
* constructName does not affect the semantics, but is used in error messages
*/
Node *
transformLimitClause(ParseState *pstate, Node *clause,
ParseExprKind exprKind, const char *constructName)
{
Node *qual;
if (clause == NULL)
return NULL;
qual = transformExpr(pstate, clause, exprKind);
qual = coerce_to_specific_type(pstate, qual, INT8OID, constructName);
/* LIMIT can't refer to any variables of the current query */
checkExprIsVarFree(pstate, qual, constructName);
return qual;
}
/*
* checkExprIsVarFree
* Check that given expr has no Vars of the current query level
* (aggregates and window functions should have been rejected already).
*
* This is used to check expressions that have to have a consistent value
* across all rows of the query, such as a LIMIT. Arguably it should reject
* volatile functions, too, but we don't do that --- whatever value the
* function gives on first execution is what you get.
*
* constructName does not affect the semantics, but is used in error messages
*/
static void
checkExprIsVarFree(ParseState *pstate, Node *n, const char *constructName)
{
if (contain_vars_of_level(n, 0))
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
/* translator: %s is name of a SQL construct, eg LIMIT */
errmsg("argument of %s must not contain variables",
constructName),
parser_errposition(pstate,
locate_var_of_level(n, 0))));
}
}
/*
* checkTargetlistEntrySQL92 -
* Validate a targetlist entry found by findTargetlistEntrySQL92
*
* When we select a pre-existing tlist entry as a result of syntax such
* as "GROUP BY 1", we have to make sure it is acceptable for use in the
* indicated clause type; transformExpr() will have treated it as a regular
* targetlist item.
*/
static void
checkTargetlistEntrySQL92(ParseState *pstate, TargetEntry *tle,
ParseExprKind exprKind)
{
switch (exprKind)
{
case EXPR_KIND_GROUP_BY:
/* reject aggregates and window functions */
if (pstate->p_hasAggs &&
contain_aggs_of_level((Node *) tle->expr, 0))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
/* translator: %s is name of a SQL construct, eg GROUP BY */
errmsg("aggregate functions are not allowed in %s",
ParseExprKindName(exprKind)),
parser_errposition(pstate,
locate_agg_of_level((Node *) tle->expr, 0))));
if (pstate->p_hasWindowFuncs &&
contain_windowfuncs((Node *) tle->expr))
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
/* translator: %s is name of a SQL construct, eg GROUP BY */
errmsg("window functions are not allowed in %s",
ParseExprKindName(exprKind)),
parser_errposition(pstate,
locate_windowfunc((Node *) tle->expr))));
break;
case EXPR_KIND_ORDER_BY:
/* no extra checks needed */
break;
case EXPR_KIND_DISTINCT_ON:
/* no extra checks needed */
break;
default:
elog(ERROR, "unexpected exprKind in checkTargetlistEntrySQL92");
break;
}
}
/*
* findTargetlistEntrySQL92 -
* Returns the targetlist entry matching the given (untransformed) node.
* If no matching entry exists, one is created and appended to the target
* list as a "resjunk" node.
*
* This function supports the old SQL92 ORDER BY interpretation, where the
* expression is an output column name or number. If we fail to find a
* match of that sort, we fall through to the SQL99 rules. For historical
* reasons, Postgres also allows this interpretation for GROUP BY, though
* the standard never did. However, for GROUP BY we prefer a SQL99 match.
* This function is *not* used for WINDOW definitions.
*
* node the ORDER BY, GROUP BY, or DISTINCT ON expression to be matched
* tlist the target list (passed by reference so we can append to it)
* exprKind identifies clause type being processed
*/
static TargetEntry *
findTargetlistEntrySQL92(ParseState *pstate, Node *node, List **tlist,
ParseExprKind exprKind)
{
ListCell *tl;
/*----------
* Handle two special cases as mandated by the SQL92 spec:
*
* 1. Bare ColumnName (no qualifier or subscripts)
* For a bare identifier, we search for a matching column name
* in the existing target list. Multiple matches are an error
* unless they refer to identical values; for example,
* we allow SELECT a, a FROM table ORDER BY a
* but not SELECT a AS b, b FROM table ORDER BY b
* If no match is found, we fall through and treat the identifier
* as an expression.
* For GROUP BY, it is incorrect to match the grouping item against
* targetlist entries: according to SQL92, an identifier in GROUP BY
* is a reference to a column name exposed by FROM, not to a target
* list column. However, many implementations (including pre-7.0
* PostgreSQL) accept this anyway. So for GROUP BY, we look first
* to see if the identifier matches any FROM column name, and only
* try for a targetlist name if it doesn't. This ensures that we
* adhere to the spec in the case where the name could be both.
* DISTINCT ON isn't in the standard, so we can do what we like there;
* we choose to make it work like ORDER BY, on the rather flimsy
* grounds that ordinary DISTINCT works on targetlist entries.
*
* 2. IntegerConstant
* This means to use the n'th item in the existing target list.
* Note that it would make no sense to order/group/distinct by an
* actual constant, so this does not create a conflict with SQL99.
* GROUP BY column-number is not allowed by SQL92, but since
* the standard has no other behavior defined for this syntax,
* we may as well accept this common extension.
*
* Note that pre-existing resjunk targets must not be used in either case,
* since the user didn't write them in his SELECT list.
*
* If neither special case applies, fall through to treat the item as
* an expression per SQL99.
*----------
*/
if (IsA(node, ColumnRef) &&
list_length(((ColumnRef *) node)->fields) == 1 &&
IsA(linitial(((ColumnRef *) node)->fields), String))
{
char *name = strVal(linitial(((ColumnRef *) node)->fields));
int location = ((ColumnRef *) node)->location;
if (exprKind == EXPR_KIND_GROUP_BY)
{
/*
* In GROUP BY, we must prefer a match against a FROM-clause
* column to one against the targetlist. Look to see if there is
* a matching column. If so, fall through to use SQL99 rules.
* NOTE: if name could refer ambiguously to more than one column
* name exposed by FROM, colNameToVar will ereport(ERROR). That's
* just what we want here.
*
* Small tweak for 7.4.3: ignore matches in upper query levels.
* This effectively changes the search order for bare names to (1)
* local FROM variables, (2) local targetlist aliases, (3) outer
* FROM variables, whereas before it was (1) (3) (2). SQL92 and
* SQL99 do not allow GROUPing BY an outer reference, so this
* breaks no cases that are legal per spec, and it seems a more
* self-consistent behavior.
*/
if (colNameToVar(pstate, name, true, location) != NULL)
name = NULL;
}
if (name != NULL)
{
TargetEntry *target_result = NULL;
foreach(tl, *tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
if (!tle->resjunk &&
strcmp(tle->resname, name) == 0)
{
if (target_result != NULL)
{
if (!equal(target_result->expr, tle->expr))
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_COLUMN),
/*------
translator: first %s is name of a SQL construct, eg ORDER BY */
errmsg("%s \"%s\" is ambiguous",
ParseExprKindName(exprKind),
name),
parser_errposition(pstate, location)));
}
else
target_result = tle;
/* Stay in loop to check for ambiguity */
}
}
if (target_result != NULL)
{
/* return the first match, after suitable validation */
checkTargetlistEntrySQL92(pstate, target_result, exprKind);
return target_result;
}
}
}
if (IsA(node, A_Const))
{
Value *val = &((A_Const *) node)->val;
int location = ((A_Const *) node)->location;
int targetlist_pos = 0;
int target_pos;
if (!IsA(val, Integer))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
/* translator: %s is name of a SQL construct, eg ORDER BY */
errmsg("non-integer constant in %s",
ParseExprKindName(exprKind)),
parser_errposition(pstate, location)));
target_pos = intVal(val);
foreach(tl, *tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
if (!tle->resjunk)
{
if (++targetlist_pos == target_pos)
{
/* return the unique match, after suitable validation */
checkTargetlistEntrySQL92(pstate, tle, exprKind);
return tle;
}
}
}
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
/* translator: %s is name of a SQL construct, eg ORDER BY */
errmsg("%s position %d is not in select list",
ParseExprKindName(exprKind), target_pos),
parser_errposition(pstate, location)));
}
/*
* Otherwise, we have an expression, so process it per SQL99 rules.
*/
return findTargetlistEntrySQL99(pstate, node, tlist, exprKind);
}
/*
* findTargetlistEntrySQL99 -
* Returns the targetlist entry matching the given (untransformed) node.
* If no matching entry exists, one is created and appended to the target
* list as a "resjunk" node.
*
* This function supports the SQL99 interpretation, wherein the expression
* is just an ordinary expression referencing input column names.
*
* node the ORDER BY, GROUP BY, etc expression to be matched
* tlist the target list (passed by reference so we can append to it)
* exprKind identifies clause type being processed
*/
static TargetEntry *
findTargetlistEntrySQL99(ParseState *pstate, Node *node, List **tlist,
ParseExprKind exprKind)
{
TargetEntry *target_result;
ListCell *tl;
Node *expr;
/*
* Convert the untransformed node to a transformed expression, and search
* for a match in the tlist. NOTE: it doesn't really matter whether there
* is more than one match. Also, we are willing to match an existing
* resjunk target here, though the SQL92 cases above must ignore resjunk
* targets.
*/
expr = transformExpr(pstate, node, exprKind);
foreach(tl, *tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tl);
Node *texpr;
/*
* Ignore any implicit cast on the existing tlist expression.
*
* This essentially allows the ORDER/GROUP/etc item to adopt the same
* datatype previously selected for a textually-equivalent tlist item.
* There can't be any implicit cast at top level in an ordinary SELECT
* tlist at this stage, but the case does arise with ORDER BY in an
* aggregate function.
*/
texpr = strip_implicit_coercions((Node *) tle->expr);
if (equal(expr, texpr))
return tle;
}
/*
* If no matches, construct a new target entry which is appended to the
* end of the target list. This target is given resjunk = true so that it
* will not be projected into the final tuple.
*/
target_result = transformTargetEntry(pstate, node, expr, exprKind,
NULL, true);
*tlist = lappend(*tlist, target_result);
return target_result;
}
/*-------------------------------------------------------------------------
* Flatten out parenthesized sublists in grouping lists, and some cases
* of nested grouping sets.
*
* Inside a grouping set (ROLLUP, CUBE, or GROUPING SETS), we expect the
* content to be nested no more than 2 deep: i.e. ROLLUP((a,b),(c,d)) is
* ok, but ROLLUP((a,(b,c)),d) is flattened to ((a,b,c),d), which we then
* (later) normalize to ((a,b,c),(d)).
*
* CUBE or ROLLUP can be nested inside GROUPING SETS (but not the reverse),
* and we leave that alone if we find it. But if we see GROUPING SETS inside
* GROUPING SETS, we can flatten and normalize as follows:
* GROUPING SETS (a, (b,c), GROUPING SETS ((c,d),(e)), (f,g))
* becomes
* GROUPING SETS ((a), (b,c), (c,d), (e), (f,g))
*
* This is per the spec's syntax transformations, but these are the only such
* transformations we do in parse analysis, so that queries retain the
* originally specified grouping set syntax for CUBE and ROLLUP as much as
* possible when deparsed. (Full expansion of the result into a list of
* grouping sets is left to the planner.)
*
* When we're done, the resulting list should contain only these possible
* elements:
* - an expression
* - a CUBE or ROLLUP with a list of expressions nested 2 deep
* - a GROUPING SET containing any of:
* - expression lists
* - empty grouping sets
* - CUBE or ROLLUP nodes with lists nested 2 deep
* The return is a new list, but doesn't deep-copy the old nodes except for
* GroupingSet nodes.
*
* As a side effect, flag whether the list has any GroupingSet nodes.
*-------------------------------------------------------------------------
*/
static Node *
flatten_grouping_sets(Node *expr, bool toplevel, bool *hasGroupingSets)
{
/* just in case of pathological input */
check_stack_depth();
if (expr == (Node *) NIL)
return (Node *) NIL;
switch (expr->type)
{
case T_RowExpr:
{
RowExpr *r = (RowExpr *) expr;
if (r->row_format == COERCE_IMPLICIT_CAST)
return flatten_grouping_sets((Node *) r->args,
false, NULL);
}
break;
case T_GroupingSet:
{
GroupingSet *gset = (GroupingSet *) expr;
ListCell *l2;
List *result_set = NIL;
if (hasGroupingSets)
*hasGroupingSets = true;
/*
* at the top level, we skip over all empty grouping sets; the
* caller can supply the canonical GROUP BY () if nothing is
* left.
*/
if (toplevel && gset->kind == GROUPING_SET_EMPTY)
return (Node *) NIL;
foreach(l2, gset->content)
{
Node *n1 = lfirst(l2);
Node *n2 = flatten_grouping_sets(n1, false, NULL);
if (IsA(n1, GroupingSet) &&
((GroupingSet *) n1)->kind == GROUPING_SET_SETS)
result_set = list_concat(result_set, (List *) n2);
else
result_set = lappend(result_set, n2);
}
/*
* At top level, keep the grouping set node; but if we're in a
* nested grouping set, then we need to concat the flattened
* result into the outer list if it's simply nested.
*/
if (toplevel || (gset->kind != GROUPING_SET_SETS))
{
return (Node *) makeGroupingSet(gset->kind, result_set, gset->location);
}
else
return (Node *) result_set;
}
case T_List:
{
List *result = NIL;
ListCell *l;
foreach(l, (List *) expr)
{
Node *n = flatten_grouping_sets(lfirst(l), toplevel, hasGroupingSets);
if (n != (Node *) NIL)
{
if (IsA(n, List))
result = list_concat(result, (List *) n);
else
result = lappend(result, n);
}
}
return (Node *) result;
}
default:
break;
}
return expr;
}
/*
* Transform a single expression within a GROUP BY clause or grouping set.
*
* The expression is added to the targetlist if not already present, and to the
* flatresult list (which will become the groupClause) if not already present
* there. The sortClause is consulted for operator and sort order hints.
*
* Returns the ressortgroupref of the expression.
*
* flatresult reference to flat list of SortGroupClause nodes
* seen_local bitmapset of sortgrouprefs already seen at the local level
* pstate ParseState
* gexpr node to transform
* targetlist reference to TargetEntry list
* sortClause ORDER BY clause (SortGroupClause nodes)
* exprKind expression kind
* useSQL99 SQL99 rather than SQL92 syntax
* toplevel false if within any grouping set
*/
static Index
transformGroupClauseExpr(List **flatresult, Bitmapset *seen_local,
ParseState *pstate, Node *gexpr,
List **targetlist, List *sortClause,
ParseExprKind exprKind, bool useSQL99, bool toplevel)
{
TargetEntry *tle;
bool found = false;
if (useSQL99)
tle = findTargetlistEntrySQL99(pstate, gexpr,
targetlist, exprKind);
else
tle = findTargetlistEntrySQL92(pstate, gexpr,
targetlist, exprKind);
if (tle->ressortgroupref > 0)
{
ListCell *sl;
/*
* Eliminate duplicates (GROUP BY x, x) but only at local level.
* (Duplicates in grouping sets can affect the number of returned
* rows, so can't be dropped indiscriminately.)
*
* Since we don't care about anything except the sortgroupref, we can
* use a bitmapset rather than scanning lists.
*/
if (bms_is_member(tle->ressortgroupref, seen_local))
return 0;
/*
* If we're already in the flat clause list, we don't need to consider
* adding ourselves again.
*/
found = targetIsInSortList(tle, InvalidOid, *flatresult);
if (found)
return tle->ressortgroupref;
/*
* If the GROUP BY tlist entry also appears in ORDER BY, copy operator
* info from the (first) matching ORDER BY item. This means that if
* you write something like "GROUP BY foo ORDER BY foo USING <<<", the
* GROUP BY operation silently takes on the equality semantics implied
* by the ORDER BY. There are two reasons to do this: it improves the
* odds that we can implement both GROUP BY and ORDER BY with a single
* sort step, and it allows the user to choose the equality semantics
* used by GROUP BY, should she be working with a datatype that has
* more than one equality operator.
*
* If we're in a grouping set, though, we force our requested ordering
* to be NULLS LAST, because if we have any hope of using a sorted agg
* for the job, we're going to be tacking on generated NULL values
* after the corresponding groups. If the user demands nulls first,
* another sort step is going to be inevitable, but that's the
* planner's problem.
*/
foreach(sl, sortClause)
{
SortGroupClause *sc = (SortGroupClause *) lfirst(sl);
if (sc->tleSortGroupRef == tle->ressortgroupref)
{
SortGroupClause *grpc = copyObject(sc);
if (!toplevel)
grpc->nulls_first = false;
*flatresult = lappend(*flatresult, grpc);
found = true;
break;
}
}
}
/*
* If no match in ORDER BY, just add it to the result using default
* sort/group semantics.
*/
if (!found)
*flatresult = addTargetToGroupList(pstate, tle,
*flatresult, *targetlist,
exprLocation(gexpr));
/*
* _something_ must have assigned us a sortgroupref by now...
*/
return tle->ressortgroupref;
}
/*
* Transform a list of expressions within a GROUP BY clause or grouping set.
*
* The list of expressions belongs to a single clause within which duplicates
* can be safely eliminated.
*
* Returns an integer list of ressortgroupref values.
*
* flatresult reference to flat list of SortGroupClause nodes
* pstate ParseState
* list nodes to transform
* targetlist reference to TargetEntry list
* sortClause ORDER BY clause (SortGroupClause nodes)
* exprKind expression kind
* useSQL99 SQL99 rather than SQL92 syntax
* toplevel false if within any grouping set
*/
static List *
transformGroupClauseList(List **flatresult,
ParseState *pstate, List *list,
List **targetlist, List *sortClause,
ParseExprKind exprKind, bool useSQL99, bool toplevel)
{
Bitmapset *seen_local = NULL;
List *result = NIL;
ListCell *gl;
foreach(gl, list)
{
Node *gexpr = (Node *) lfirst(gl);
Index ref = transformGroupClauseExpr(flatresult,
seen_local,
pstate,
gexpr,
targetlist,
sortClause,
exprKind,
useSQL99,
toplevel);
if (ref > 0)
{
seen_local = bms_add_member(seen_local, ref);
result = lappend_int(result, ref);
}
}
return result;
}
/*
* Transform a grouping set and (recursively) its content.
*
* The grouping set might be a GROUPING SETS node with other grouping sets
* inside it, but SETS within SETS have already been flattened out before
* reaching here.
*
* Returns the transformed node, which now contains SIMPLE nodes with lists
* of ressortgrouprefs rather than expressions.
*
* flatresult reference to flat list of SortGroupClause nodes
* pstate ParseState
* gset grouping set to transform
* targetlist reference to TargetEntry list
* sortClause ORDER BY clause (SortGroupClause nodes)
* exprKind expression kind
* useSQL99 SQL99 rather than SQL92 syntax
* toplevel false if within any grouping set
*/
static Node *
transformGroupingSet(List **flatresult,
ParseState *pstate, GroupingSet *gset,
List **targetlist, List *sortClause,
ParseExprKind exprKind, bool useSQL99, bool toplevel)
{
ListCell *gl;
List *content = NIL;
Assert(toplevel || gset->kind != GROUPING_SET_SETS);
foreach(gl, gset->content)
{
Node *n = lfirst(gl);
if (IsA(n, List))
{
List *l = transformGroupClauseList(flatresult,
pstate, (List *) n,
targetlist, sortClause,
exprKind, useSQL99, false);
content = lappend(content, makeGroupingSet(GROUPING_SET_SIMPLE,
l,
exprLocation(n)));
}
else if (IsA(n, GroupingSet))
{
GroupingSet *gset2 = (GroupingSet *) lfirst(gl);
content = lappend(content, transformGroupingSet(flatresult,
pstate, gset2,
targetlist, sortClause,
exprKind, useSQL99, false));
}
else
{
Index ref = transformGroupClauseExpr(flatresult,
NULL,
pstate,
n,
targetlist,
sortClause,
exprKind,
useSQL99,
false);
content = lappend(content, makeGroupingSet(GROUPING_SET_SIMPLE,
list_make1_int(ref),
exprLocation(n)));
}
}
/* Arbitrarily cap the size of CUBE, which has exponential growth */
if (gset->kind == GROUPING_SET_CUBE)
{
if (list_length(content) > 12)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("CUBE is limited to 12 elements"),
parser_errposition(pstate, gset->location)));
}
return (Node *) makeGroupingSet(gset->kind, content, gset->location);
}
/*
* transformGroupClause -
* transform a GROUP BY clause
*
* GROUP BY items will be added to the targetlist (as resjunk columns)
* if not already present, so the targetlist must be passed by reference.
*
* This is also used for window PARTITION BY clauses (which act almost the
* same, but are always interpreted per SQL99 rules).
*
* Grouping sets make this a lot more complex than it was. Our goal here is
* twofold: we make a flat list of SortGroupClause nodes referencing each
* distinct expression used for grouping, with those expressions added to the
* targetlist if needed. At the same time, we build the groupingSets tree,
* which stores only ressortgrouprefs as integer lists inside GroupingSet nodes
* (possibly nested, but limited in depth: a GROUPING_SET_SETS node can contain
* nested SIMPLE, CUBE or ROLLUP nodes, but not more sets - we flatten that
* out; while CUBE and ROLLUP can contain only SIMPLE nodes).
*
* We skip much of the hard work if there are no grouping sets.
*
* One subtlety is that the groupClause list can end up empty while the
* groupingSets list is not; this happens if there are only empty grouping
* sets, or an explicit GROUP BY (). This has the same effect as specifying
* aggregates or a HAVING clause with no GROUP BY; the output is one row per
* grouping set even if the input is empty.
*
* Returns the transformed (flat) groupClause.
*
* pstate ParseState
* grouplist clause to transform
* groupingSets reference to list to contain the grouping set tree
* targetlist reference to TargetEntry list
* sortClause ORDER BY clause (SortGroupClause nodes)
* exprKind expression kind
* useSQL99 SQL99 rather than SQL92 syntax
*/
List *
transformGroupClause(ParseState *pstate, List *grouplist, List **groupingSets,
List **targetlist, List *sortClause,
ParseExprKind exprKind, bool useSQL99)
{
List *result = NIL;
List *flat_grouplist;
List *gsets = NIL;
ListCell *gl;
bool hasGroupingSets = false;
Bitmapset *seen_local = NULL;
/*
* Recursively flatten implicit RowExprs. (Technically this is only needed
* for GROUP BY, per the syntax rules for grouping sets, but we do it
* anyway.)
*/
flat_grouplist = (List *) flatten_grouping_sets((Node *) grouplist,
true,
&hasGroupingSets);
/*
* If the list is now empty, but hasGroupingSets is true, it's because we
* elided redundant empty grouping sets. Restore a single empty grouping
* set to leave a canonical form: GROUP BY ()
*/
if (flat_grouplist == NIL && hasGroupingSets)
{
flat_grouplist = list_make1(makeGroupingSet(GROUPING_SET_EMPTY,
NIL,
exprLocation((Node *) grouplist)));
}
foreach(gl, flat_grouplist)
{
Node *gexpr = (Node *) lfirst(gl);
if (IsA(gexpr, GroupingSet))
{
GroupingSet *gset = (GroupingSet *) gexpr;
switch (gset->kind)
{
case GROUPING_SET_EMPTY:
gsets = lappend(gsets, gset);
break;
case GROUPING_SET_SIMPLE:
/* can't happen */
Assert(false);
break;
case GROUPING_SET_SETS:
case GROUPING_SET_CUBE:
case GROUPING_SET_ROLLUP:
gsets = lappend(gsets,
transformGroupingSet(&result,
pstate, gset,
targetlist, sortClause,
exprKind, useSQL99, true));
break;
}
}
else
{
Index ref = transformGroupClauseExpr(&result, seen_local,
pstate, gexpr,
targetlist, sortClause,
exprKind, useSQL99, true);
if (ref > 0)
{
seen_local = bms_add_member(seen_local, ref);
if (hasGroupingSets)
gsets = lappend(gsets,
makeGroupingSet(GROUPING_SET_SIMPLE,
list_make1_int(ref),
exprLocation(gexpr)));
}
}
}
/* parser should prevent this */
Assert(gsets == NIL || groupingSets != NULL);
if (groupingSets)
*groupingSets = gsets;
return result;
}
/*
* transformSortClause -
* transform an ORDER BY clause
*
* ORDER BY items will be added to the targetlist (as resjunk columns)
* if not already present, so the targetlist must be passed by reference.
*
* This is also used for window and aggregate ORDER BY clauses (which act
* almost the same, but are always interpreted per SQL99 rules).
*/
List *
transformSortClause(ParseState *pstate,
List *orderlist,
List **targetlist,
ParseExprKind exprKind,
bool useSQL99)
{
List *sortlist = NIL;
ListCell *olitem;
foreach(olitem, orderlist)
{
SortBy *sortby = (SortBy *) lfirst(olitem);
TargetEntry *tle;
if (useSQL99)
tle = findTargetlistEntrySQL99(pstate, sortby->node,
targetlist, exprKind);
else
tle = findTargetlistEntrySQL92(pstate, sortby->node,
targetlist, exprKind);
sortlist = addTargetToSortList(pstate, tle,
sortlist, *targetlist, sortby);
}
return sortlist;
}
/*
* transformWindowDefinitions -
* transform window definitions (WindowDef to WindowClause)
*/
List *
transformWindowDefinitions(ParseState *pstate,
List *windowdefs,
List **targetlist)
{
List *result = NIL;
Index winref = 0;
ListCell *lc;
foreach(lc, windowdefs)
{
WindowDef *windef = (WindowDef *) lfirst(lc);
WindowClause *refwc = NULL;
List *partitionClause;
List *orderClause;
Oid rangeopfamily = InvalidOid;
Oid rangeopcintype = InvalidOid;
WindowClause *wc;
winref++;
/*
* Check for duplicate window names.
*/
if (windef->name &&
findWindowClause(result, windef->name) != NULL)
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
errmsg("window \"%s\" is already defined", windef->name),
parser_errposition(pstate, windef->location)));
/*
* If it references a previous window, look that up.
*/
if (windef->refname)
{
refwc = findWindowClause(result, windef->refname);
if (refwc == NULL)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("window \"%s\" does not exist",
windef->refname),
parser_errposition(pstate, windef->location)));
}
/*
* Transform PARTITION and ORDER specs, if any. These are treated
* almost exactly like top-level GROUP BY and ORDER BY clauses,
* including the special handling of nondefault operator semantics.
*/
orderClause = transformSortClause(pstate,
windef->orderClause,
targetlist,
EXPR_KIND_WINDOW_ORDER,
true /* force SQL99 rules */ );
partitionClause = transformGroupClause(pstate,
windef->partitionClause,
NULL,
targetlist,
orderClause,
EXPR_KIND_WINDOW_PARTITION,
true /* force SQL99 rules */ );
/*
* And prepare the new WindowClause.
*/
wc = makeNode(WindowClause);
wc->name = windef->name;
wc->refname = windef->refname;
/*
* Per spec, a windowdef that references a previous one copies the
* previous partition clause (and mustn't specify its own). It can
* specify its own ordering clause, but only if the previous one had
* none. It always specifies its own frame clause, and the previous
* one must not have a frame clause. Yeah, it's bizarre that each of
* these cases works differently, but SQL:2008 says so; see 7.11
* <window clause> syntax rule 10 and general rule 1. The frame
* clause rule is especially bizarre because it makes "OVER foo"
* different from "OVER (foo)", and requires the latter to throw an
* error if foo has a nondefault frame clause. Well, ours not to
* reason why, but we do go out of our way to throw a useful error
* message for such cases.
*/
if (refwc)
{
if (partitionClause)
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
errmsg("cannot override PARTITION BY clause of window \"%s\"",
windef->refname),
parser_errposition(pstate, windef->location)));
wc->partitionClause = copyObject(refwc->partitionClause);
}
else
wc->partitionClause = partitionClause;
if (refwc)
{
if (orderClause && refwc->orderClause)
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
errmsg("cannot override ORDER BY clause of window \"%s\"",
windef->refname),
parser_errposition(pstate, windef->location)));
if (orderClause)
{
wc->orderClause = orderClause;
wc->copiedOrder = false;
}
else
{
wc->orderClause = copyObject(refwc->orderClause);
wc->copiedOrder = true;
}
}
else
{
wc->orderClause = orderClause;
wc->copiedOrder = false;
}
if (refwc && refwc->frameOptions != FRAMEOPTION_DEFAULTS)
{
/*
* Use this message if this is a WINDOW clause, or if it's an OVER
* clause that includes ORDER BY or framing clauses. (We already
* rejected PARTITION BY above, so no need to check that.)
*/
if (windef->name ||
orderClause || windef->frameOptions != FRAMEOPTION_DEFAULTS)
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
errmsg("cannot copy window \"%s\" because it has a frame clause",
windef->refname),
parser_errposition(pstate, windef->location)));
/* Else this clause is just OVER (foo), so say this: */
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
errmsg("cannot copy window \"%s\" because it has a frame clause",
windef->refname),
errhint("Omit the parentheses in this OVER clause."),
parser_errposition(pstate, windef->location)));
}
wc->frameOptions = windef->frameOptions;
/*
* RANGE offset PRECEDING/FOLLOWING requires exactly one ORDER BY
* column; check that and get its sort opfamily info.
*/
if ((wc->frameOptions & FRAMEOPTION_RANGE) &&
(wc->frameOptions & (FRAMEOPTION_START_OFFSET |
FRAMEOPTION_END_OFFSET)))
{
SortGroupClause *sortcl;
Node *sortkey;
int16 rangestrategy;
if (list_length(wc->orderClause) != 1)
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
errmsg("RANGE with offset PRECEDING/FOLLOWING requires exactly one ORDER BY column"),
parser_errposition(pstate, windef->location)));
sortcl = castNode(SortGroupClause, linitial(wc->orderClause));
sortkey = get_sortgroupclause_expr(sortcl, *targetlist);
/* Find the sort operator in pg_amop */
if (!get_ordering_op_properties(sortcl->sortop,
&rangeopfamily,
&rangeopcintype,
&rangestrategy))
elog(ERROR, "operator %u is not a valid ordering operator",
sortcl->sortop);
/* Record properties of sort ordering */
wc->inRangeColl = exprCollation(sortkey);
wc->inRangeAsc = (rangestrategy == BTLessStrategyNumber);
wc->inRangeNullsFirst = sortcl->nulls_first;
}
/* Per spec, GROUPS mode requires an ORDER BY clause */
if (wc->frameOptions & FRAMEOPTION_GROUPS)
{
if (wc->orderClause == NIL)
ereport(ERROR,
(errcode(ERRCODE_WINDOWING_ERROR),
errmsg("GROUPS mode requires an ORDER BY clause"),
parser_errposition(pstate, windef->location)));
}
/* Process frame offset expressions */
wc->startOffset = transformFrameOffset(pstate, wc->frameOptions,
rangeopfamily, rangeopcintype,
&wc->startInRangeFunc,
windef->startOffset);
wc->endOffset = transformFrameOffset(pstate, wc->frameOptions,
rangeopfamily, rangeopcintype,
&wc->endInRangeFunc,
windef->endOffset);
wc->winref = winref;
result = lappend(result, wc);
}
return result;
}
/*
* transformDistinctClause -
* transform a DISTINCT clause
*
* Since we may need to add items to the query's targetlist, that list
* is passed by reference.
*
* As with GROUP BY, we absorb the sorting semantics of ORDER BY as much as
* possible into the distinctClause. This avoids a possible need to re-sort,
* and allows the user to choose the equality semantics used by DISTINCT,
* should she be working with a datatype that has more than one equality
* operator.
*
* is_agg is true if we are transforming an aggregate(DISTINCT ...)
* function call. This does not affect any behavior, only the phrasing
* of error messages.
*/
List *
transformDistinctClause(ParseState *pstate,
List **targetlist, List *sortClause, bool is_agg)
{
List *result = NIL;
ListCell *slitem;
ListCell *tlitem;
/*
* The distinctClause should consist of all ORDER BY items followed by all
* other non-resjunk targetlist items. There must not be any resjunk
* ORDER BY items --- that would imply that we are sorting by a value that
* isn't necessarily unique within a DISTINCT group, so the results
* wouldn't be well-defined. This construction ensures we follow the rule
* that sortClause and distinctClause match; in fact the sortClause will
* always be a prefix of distinctClause.
*
* Note a corner case: the same TLE could be in the ORDER BY list multiple
* times with different sortops. We have to include it in the
* distinctClause the same way to preserve the prefix property. The net
* effect will be that the TLE value will be made unique according to both
* sortops.
*/
foreach(slitem, sortClause)
{
SortGroupClause *scl = (SortGroupClause *) lfirst(slitem);
TargetEntry *tle = get_sortgroupclause_tle(scl, *targetlist);
if (tle->resjunk)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
is_agg ?
errmsg("in an aggregate with DISTINCT, ORDER BY expressions must appear in argument list") :
errmsg("for SELECT DISTINCT, ORDER BY expressions must appear in select list"),
parser_errposition(pstate,
exprLocation((Node *) tle->expr))));
result = lappend(result, copyObject(scl));
}
/*
* Now add any remaining non-resjunk tlist items, using default sort/group
* semantics for their data types.
*/
foreach(tlitem, *targetlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tlitem);
if (tle->resjunk)
continue; /* ignore junk */
result = addTargetToGroupList(pstate, tle,
result, *targetlist,
exprLocation((Node *) tle->expr));
}
/*
* Complain if we found nothing to make DISTINCT. Returning an empty list
* would cause the parsed Query to look like it didn't have DISTINCT, with
* results that would probably surprise the user. Note: this case is
* presently impossible for aggregates because of grammar restrictions,
* but we check anyway.
*/
if (result == NIL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
is_agg ?
errmsg("an aggregate with DISTINCT must have at least one argument") :
errmsg("SELECT DISTINCT must have at least one column")));
return result;
}
/*
* transformDistinctOnClause -
* transform a DISTINCT ON clause
*
* Since we may need to add items to the query's targetlist, that list
* is passed by reference.
*
* As with GROUP BY, we absorb the sorting semantics of ORDER BY as much as
* possible into the distinctClause. This avoids a possible need to re-sort,
* and allows the user to choose the equality semantics used by DISTINCT,
* should she be working with a datatype that has more than one equality
* operator.
*/
List *
transformDistinctOnClause(ParseState *pstate, List *distinctlist,
List **targetlist, List *sortClause)
{
List *result = NIL;
List *sortgrouprefs = NIL;
bool skipped_sortitem;
ListCell *lc;
ListCell *lc2;
/*
* Add all the DISTINCT ON expressions to the tlist (if not already
* present, they are added as resjunk items). Assign sortgroupref numbers
* to them, and make a list of these numbers. (NB: we rely below on the
* sortgrouprefs list being one-for-one with the original distinctlist.
* Also notice that we could have duplicate DISTINCT ON expressions and
* hence duplicate entries in sortgrouprefs.)
*/
foreach(lc, distinctlist)
{
Node *dexpr = (Node *) lfirst(lc);
int sortgroupref;
TargetEntry *tle;
tle = findTargetlistEntrySQL92(pstate, dexpr, targetlist,
EXPR_KIND_DISTINCT_ON);
sortgroupref = assignSortGroupRef(tle, *targetlist);
sortgrouprefs = lappend_int(sortgrouprefs, sortgroupref);
}
/*
* If the user writes both DISTINCT ON and ORDER BY, adopt the sorting
* semantics from ORDER BY items that match DISTINCT ON items, and also
* adopt their column sort order. We insist that the distinctClause and
* sortClause match, so throw error if we find the need to add any more
* distinctClause items after we've skipped an ORDER BY item that wasn't
* in DISTINCT ON.
*/
skipped_sortitem = false;
foreach(lc, sortClause)
{
SortGroupClause *scl = (SortGroupClause *) lfirst(lc);
if (list_member_int(sortgrouprefs, scl->tleSortGroupRef))
{
if (skipped_sortitem)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("SELECT DISTINCT ON expressions must match initial ORDER BY expressions"),
parser_errposition(pstate,
get_matching_location(scl->tleSortGroupRef,
sortgrouprefs,
distinctlist))));
else
result = lappend(result, copyObject(scl));
}
else
skipped_sortitem = true;
}
/*
* Now add any remaining DISTINCT ON items, using default sort/group
* semantics for their data types. (Note: this is pretty questionable; if
* the ORDER BY list doesn't include all the DISTINCT ON items and more
* besides, you certainly aren't using DISTINCT ON in the intended way,
* and you probably aren't going to get consistent results. It might be
* better to throw an error or warning here. But historically we've
* allowed it, so keep doing so.)
*/
forboth(lc, distinctlist, lc2, sortgrouprefs)
{
Node *dexpr = (Node *) lfirst(lc);
int sortgroupref = lfirst_int(lc2);
TargetEntry *tle = get_sortgroupref_tle(sortgroupref, *targetlist);
if (targetIsInSortList(tle, InvalidOid, result))
continue; /* already in list (with some semantics) */
if (skipped_sortitem)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("SELECT DISTINCT ON expressions must match initial ORDER BY expressions"),
parser_errposition(pstate, exprLocation(dexpr))));
result = addTargetToGroupList(pstate, tle,
result, *targetlist,
exprLocation(dexpr));
}
/*
* An empty result list is impossible here because of grammar
* restrictions.
*/
Assert(result != NIL);
return result;
}
/*
* get_matching_location
* Get the exprLocation of the exprs member corresponding to the
* (first) member of sortgrouprefs that equals sortgroupref.
*
* This is used so that we can point at a troublesome DISTINCT ON entry.
* (Note that we need to use the original untransformed DISTINCT ON list
* item, as whatever TLE it corresponds to will very possibly have a
* parse location pointing to some matching entry in the SELECT list
* or ORDER BY list.)
*/
static int
get_matching_location(int sortgroupref, List *sortgrouprefs, List *exprs)
{
ListCell *lcs;
ListCell *lce;
forboth(lcs, sortgrouprefs, lce, exprs)
{
if (lfirst_int(lcs) == sortgroupref)
return exprLocation((Node *) lfirst(lce));
}
/* if no match, caller blew it */
elog(ERROR, "get_matching_location: no matching sortgroupref");
return -1; /* keep compiler quiet */
}
/*
* resolve_unique_index_expr
* Infer a unique index from a list of indexElems, for ON
* CONFLICT clause
*
* Perform parse analysis of expressions and columns appearing within ON
* CONFLICT clause. During planning, the returned list of expressions is used
* to infer which unique index to use.
*/
static List *
resolve_unique_index_expr(ParseState *pstate, InferClause *infer,
Relation heapRel)
{
List *result = NIL;
ListCell *l;
foreach(l, infer->indexElems)
{
IndexElem *ielem = (IndexElem *) lfirst(l);
InferenceElem *pInfer = makeNode(InferenceElem);
Node *parse;
/*
* Raw grammar re-uses CREATE INDEX infrastructure for unique index
* inference clause, and so will accept opclasses by name and so on.
*
* Make no attempt to match ASC or DESC ordering or NULLS FIRST/NULLS
* LAST ordering, since those are not significant for inference
* purposes (any unique index matching the inference specification in
* other regards is accepted indifferently). Actively reject this as
* wrong-headed.
*/
if (ielem->ordering != SORTBY_DEFAULT)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("ASC/DESC is not allowed in ON CONFLICT clause"),
parser_errposition(pstate,
exprLocation((Node *) infer))));
if (ielem->nulls_ordering != SORTBY_NULLS_DEFAULT)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("NULLS FIRST/LAST is not allowed in ON CONFLICT clause"),
parser_errposition(pstate,
exprLocation((Node *) infer))));
if (!ielem->expr)
{
/* Simple index attribute */
ColumnRef *n;
/*
* Grammar won't have built raw expression for us in event of
* plain column reference. Create one directly, and perform
* expression transformation. Planner expects this, and performs
* its own normalization for the purposes of matching against
* pg_index.
*/
n = makeNode(ColumnRef);
n->fields = list_make1(makeString(ielem->name));
/* Location is approximately that of inference specification */
n->location = infer->location;
parse = (Node *) n;
}
else
{
/* Do parse transformation of the raw expression */
parse = (Node *) ielem->expr;
}
/*
* transformExpr() will reject subqueries, aggregates, window
* functions, and SRFs, based on being passed
* EXPR_KIND_INDEX_EXPRESSION. So we needn't worry about those
* further ... not that they would match any available index
* expression anyway.
*/
pInfer->expr = transformExpr(pstate, parse, EXPR_KIND_INDEX_EXPRESSION);
/* Perform lookup of collation and operator class as required */
if (!ielem->collation)
pInfer->infercollid = InvalidOid;
else
pInfer->infercollid = LookupCollation(pstate, ielem->collation,
exprLocation(pInfer->expr));
if (!ielem->opclass)
pInfer->inferopclass = InvalidOid;
else
pInfer->inferopclass = get_opclass_oid(BTREE_AM_OID,
ielem->opclass, false);
result = lappend(result, pInfer);
}
return result;
}
/*
* transformOnConflictArbiter -
* transform arbiter expressions in an ON CONFLICT clause.
*
* Transformed expressions used to infer one unique index relation to serve as
* an ON CONFLICT arbiter. Partial unique indexes may be inferred using WHERE
* clause from inference specification clause.
*/
void
transformOnConflictArbiter(ParseState *pstate,
OnConflictClause *onConflictClause,
List **arbiterExpr, Node **arbiterWhere,
Oid *constraint)
{
InferClause *infer = onConflictClause->infer;
*arbiterExpr = NIL;
*arbiterWhere = NULL;
*constraint = InvalidOid;
if (onConflictClause->action == ONCONFLICT_UPDATE && !infer)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("ON CONFLICT DO UPDATE requires inference specification or constraint name"),
errhint("For example, ON CONFLICT (column_name)."),
parser_errposition(pstate,
exprLocation((Node *) onConflictClause))));
/*
* To simplify certain aspects of its design, speculative insertion into
* system catalogs is disallowed
*/
if (IsCatalogRelation(pstate->p_target_relation))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("ON CONFLICT is not supported with system catalog tables"),
parser_errposition(pstate,
exprLocation((Node *) onConflictClause))));
/* Same applies to table used by logical decoding as catalog table */
if (RelationIsUsedAsCatalogTable(pstate->p_target_relation))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("ON CONFLICT is not supported on table \"%s\" used as a catalog table",
RelationGetRelationName(pstate->p_target_relation)),
parser_errposition(pstate,
exprLocation((Node *) onConflictClause))));
/* ON CONFLICT DO NOTHING does not require an inference clause */
if (infer)
{
List *save_namespace;
/*
* While we process the arbiter expressions, accept only non-qualified
* references to the target table. Hide any other relations.
*/
save_namespace = pstate->p_namespace;
pstate->p_namespace = NIL;
addRTEtoQuery(pstate, pstate->p_target_rangetblentry,
false, false, true);
if (infer->indexElems)
*arbiterExpr = resolve_unique_index_expr(pstate, infer,
pstate->p_target_relation);
/*
* Handling inference WHERE clause (for partial unique index
* inference)
*/
if (infer->whereClause)
*arbiterWhere = transformExpr(pstate, infer->whereClause,
EXPR_KIND_INDEX_PREDICATE);
pstate->p_namespace = save_namespace;
/*
* If the arbiter is specified by constraint name, get the constraint
* OID and mark the constrained columns as requiring SELECT privilege,
* in the same way as would have happened if the arbiter had been
* specified by explicit reference to the constraint's index columns.
*/
if (infer->conname)
{
Oid relid = RelationGetRelid(pstate->p_target_relation);
RangeTblEntry *rte = pstate->p_target_rangetblentry;
Bitmapset *conattnos;
conattnos = get_relation_constraint_attnos(relid, infer->conname,
false, constraint);
/* Make sure the rel as a whole is marked for SELECT access */
rte->requiredPerms |= ACL_SELECT;
/* Mark the constrained columns as requiring SELECT access */
rte->selectedCols = bms_add_members(rte->selectedCols, conattnos);
}
}
/*
* It's convenient to form a list of expressions based on the
* representation used by CREATE INDEX, since the same restrictions are
* appropriate (e.g. on subqueries). However, from here on, a dedicated
* primnode representation is used for inference elements, and so
* assign_query_collations() can be trusted to do the right thing with the
* post parse analysis query tree inference clause representation.
*/
}
/*
* addTargetToSortList
* If the given targetlist entry isn't already in the SortGroupClause
* list, add it to the end of the list, using the given sort ordering
* info.
*
* Returns the updated SortGroupClause list.
*/
List *
addTargetToSortList(ParseState *pstate, TargetEntry *tle,
List *sortlist, List *targetlist, SortBy *sortby)
{
Oid restype = exprType((Node *) tle->expr);
Oid sortop;
Oid eqop;
bool hashable;
bool reverse;
int location;
ParseCallbackState pcbstate;
/* if tlist item is an UNKNOWN literal, change it to TEXT */
if (restype == UNKNOWNOID)
{
tle->expr = (Expr *) coerce_type(pstate, (Node *) tle->expr,
restype, TEXTOID, -1,
COERCION_IMPLICIT,
COERCE_IMPLICIT_CAST,
-1);
restype = TEXTOID;
}
/*
* Rather than clutter the API of get_sort_group_operators and the other
* functions we're about to use, make use of error context callback to
* mark any error reports with a parse position. We point to the operator
* location if present, else to the expression being sorted. (NB: use the
* original untransformed expression here; the TLE entry might well point
* at a duplicate expression in the regular SELECT list.)
*/
location = sortby->location;
if (location < 0)
location = exprLocation(sortby->node);
setup_parser_errposition_callback(&pcbstate, pstate, location);
/* determine the sortop, eqop, and directionality */
switch (sortby->sortby_dir)
{
case SORTBY_DEFAULT:
case SORTBY_ASC:
get_sort_group_operators(restype,
true, true, false,
&sortop, &eqop, NULL,
&hashable);
reverse = false;
break;
case SORTBY_DESC:
get_sort_group_operators(restype,
false, true, true,
NULL, &eqop, &sortop,
&hashable);
reverse = true;
break;
case SORTBY_USING:
Assert(sortby->useOp != NIL);
sortop = compatible_oper_opid(sortby->useOp,
restype,
restype,
false);
/*
* Verify it's a valid ordering operator, fetch the corresponding
* equality operator, and determine whether to consider it like
* ASC or DESC.
*/
eqop = get_equality_op_for_ordering_op(sortop, &reverse);
if (!OidIsValid(eqop))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("operator %s is not a valid ordering operator",
strVal(llast(sortby->useOp))),
errhint("Ordering operators must be \"<\" or \">\" members of btree operator families.")));
/*
* Also see if the equality operator is hashable.
*/
hashable = op_hashjoinable(eqop, restype);
break;
default:
elog(ERROR, "unrecognized sortby_dir: %d", sortby->sortby_dir);
sortop = InvalidOid; /* keep compiler quiet */
eqop = InvalidOid;
hashable = false;
reverse = false;
break;
}
cancel_parser_errposition_callback(&pcbstate);
/* avoid making duplicate sortlist entries */
if (!targetIsInSortList(tle, sortop, sortlist))
{
SortGroupClause *sortcl = makeNode(SortGroupClause);
sortcl->tleSortGroupRef = assignSortGroupRef(tle, targetlist);
sortcl->eqop = eqop;
sortcl->sortop = sortop;
sortcl->hashable = hashable;
switch (sortby->sortby_nulls)
{
case SORTBY_NULLS_DEFAULT:
/* NULLS FIRST is default for DESC; other way for ASC */
sortcl->nulls_first = reverse;
break;
case SORTBY_NULLS_FIRST:
sortcl->nulls_first = true;
break;
case SORTBY_NULLS_LAST:
sortcl->nulls_first = false;
break;
default:
elog(ERROR, "unrecognized sortby_nulls: %d",
sortby->sortby_nulls);
break;
}
sortlist = lappend(sortlist, sortcl);
}
return sortlist;
}
/*
* addTargetToGroupList
* If the given targetlist entry isn't already in the SortGroupClause
* list, add it to the end of the list, using default sort/group
* semantics.
*
* This is very similar to addTargetToSortList, except that we allow the
* case where only a grouping (equality) operator can be found, and that
* the TLE is considered "already in the list" if it appears there with any
* sorting semantics.
*
* location is the parse location to be fingered in event of trouble. Note
* that we can't rely on exprLocation(tle->expr), because that might point
* to a SELECT item that matches the GROUP BY item; it'd be pretty confusing
* to report such a location.
*
* Returns the updated SortGroupClause list.
*/
static List *
addTargetToGroupList(ParseState *pstate, TargetEntry *tle,
List *grouplist, List *targetlist, int location)
{
Oid restype = exprType((Node *) tle->expr);
/* if tlist item is an UNKNOWN literal, change it to TEXT */
if (restype == UNKNOWNOID)
{
tle->expr = (Expr *) coerce_type(pstate, (Node *) tle->expr,
restype, TEXTOID, -1,
COERCION_IMPLICIT,
COERCE_IMPLICIT_CAST,
-1);
restype = TEXTOID;
}
/* avoid making duplicate grouplist entries */
if (!targetIsInSortList(tle, InvalidOid, grouplist))
{
SortGroupClause *grpcl = makeNode(SortGroupClause);
Oid sortop;
Oid eqop;
bool hashable;
ParseCallbackState pcbstate;
setup_parser_errposition_callback(&pcbstate, pstate, location);
/* determine the eqop and optional sortop */
get_sort_group_operators(restype,
false, true, false,
&sortop, &eqop, NULL,
&hashable);
cancel_parser_errposition_callback(&pcbstate);
grpcl->tleSortGroupRef = assignSortGroupRef(tle, targetlist);
grpcl->eqop = eqop;
grpcl->sortop = sortop;
grpcl->nulls_first = false; /* OK with or without sortop */
grpcl->hashable = hashable;
grouplist = lappend(grouplist, grpcl);
}
return grouplist;
}
/*
* assignSortGroupRef
* Assign the targetentry an unused ressortgroupref, if it doesn't
* already have one. Return the assigned or pre-existing refnumber.
*
* 'tlist' is the targetlist containing (or to contain) the given targetentry.
*/
Index
assignSortGroupRef(TargetEntry *tle, List *tlist)
{
Index maxRef;
ListCell *l;
if (tle->ressortgroupref) /* already has one? */
return tle->ressortgroupref;
/* easiest way to pick an unused refnumber: max used + 1 */
maxRef = 0;
foreach(l, tlist)
{
Index ref = ((TargetEntry *) lfirst(l))->ressortgroupref;
if (ref > maxRef)
maxRef = ref;
}
tle->ressortgroupref = maxRef + 1;
return tle->ressortgroupref;
}
/*
* targetIsInSortList
* Is the given target item already in the sortlist?
* If sortop is not InvalidOid, also test for a match to the sortop.
*
* It is not an oversight that this function ignores the nulls_first flag.
* We check sortop when determining if an ORDER BY item is redundant with
* earlier ORDER BY items, because it's conceivable that "ORDER BY
* foo USING <, foo USING <<<" is not redundant, if <<< distinguishes
* values that < considers equal. We need not check nulls_first
* however, because a lower-order column with the same sortop but
* opposite nulls direction is redundant. Also, we can consider
* ORDER BY foo ASC, foo DESC redundant, so check for a commutator match.
*
* Works for both ordering and grouping lists (sortop would normally be
* InvalidOid when considering grouping). Note that the main reason we need
* this routine (and not just a quick test for nonzeroness of ressortgroupref)
* is that a TLE might be in only one of the lists.
*/
bool
targetIsInSortList(TargetEntry *tle, Oid sortop, List *sortList)
{
Index ref = tle->ressortgroupref;
ListCell *l;
/* no need to scan list if tle has no marker */
if (ref == 0)
return false;
foreach(l, sortList)
{
SortGroupClause *scl = (SortGroupClause *) lfirst(l);
if (scl->tleSortGroupRef == ref &&
(sortop == InvalidOid ||
sortop == scl->sortop ||
sortop == get_commutator(scl->sortop)))
return true;
}
return false;
}
/*
* findWindowClause
* Find the named WindowClause in the list, or return NULL if not there
*/
static WindowClause *
findWindowClause(List *wclist, const char *name)
{
ListCell *l;
foreach(l, wclist)
{
WindowClause *wc = (WindowClause *) lfirst(l);
if (wc->name && strcmp(wc->name, name) == 0)
return wc;
}
return NULL;
}
/*
* transformFrameOffset
* Process a window frame offset expression
*
* In RANGE mode, rangeopfamily is the sort opfamily for the input ORDER BY
* column, and rangeopcintype is the input data type the sort operator is
* registered with. We expect the in_range function to be registered with
* that same type. (In binary-compatible cases, it might be different from
* the input column's actual type, so we can't use that for the lookups.)
* We'll return the OID of the in_range function to *inRangeFunc.
*/
static Node *
transformFrameOffset(ParseState *pstate, int frameOptions,
Oid rangeopfamily, Oid rangeopcintype, Oid *inRangeFunc,
Node *clause)
{
const char *constructName = NULL;
Node *node;
*inRangeFunc = InvalidOid; /* default result */
/* Quick exit if no offset expression */
if (clause == NULL)
return NULL;
if (frameOptions & FRAMEOPTION_ROWS)
{
/* Transform the raw expression tree */
node = transformExpr(pstate, clause, EXPR_KIND_WINDOW_FRAME_ROWS);
/*
* Like LIMIT clause, simply coerce to int8
*/
constructName = "ROWS";
node = coerce_to_specific_type(pstate, node, INT8OID, constructName);
}
else if (frameOptions & FRAMEOPTION_RANGE)
{
/*
* We must look up the in_range support function that's to be used,
* possibly choosing one of several, and coerce the "offset" value to
* the appropriate input type.
*/
Oid nodeType;
Oid preferredType;
int nfuncs = 0;
int nmatches = 0;
Oid selectedType = InvalidOid;
Oid selectedFunc = InvalidOid;
CatCList *proclist;
int i;
/* Transform the raw expression tree */
node = transformExpr(pstate, clause, EXPR_KIND_WINDOW_FRAME_RANGE);
nodeType = exprType(node);
/*
* If there are multiple candidates, we'll prefer the one that exactly
* matches nodeType; or if nodeType is as yet unknown, prefer the one
* that exactly matches the sort column type. (The second rule is
* like what we do for "known_type operator unknown".)
*/
preferredType = (nodeType != UNKNOWNOID) ? nodeType : rangeopcintype;
/* Find the in_range support functions applicable to this case */
proclist = SearchSysCacheList2(AMPROCNUM,
ObjectIdGetDatum(rangeopfamily),
ObjectIdGetDatum(rangeopcintype));
for (i = 0; i < proclist->n_members; i++)
{
HeapTuple proctup = &proclist->members[i]->tuple;
Form_pg_amproc procform = (Form_pg_amproc) GETSTRUCT(proctup);
/* The search will find all support proc types; ignore others */
if (procform->amprocnum != BTINRANGE_PROC)
continue;
nfuncs++;
/* Ignore function if given value can't be coerced to that type */
if (!can_coerce_type(1, &nodeType, &procform->amprocrighttype,
COERCION_IMPLICIT))
continue;
nmatches++;
/* Remember preferred match, or any match if didn't find that */
if (selectedType != preferredType)
{
selectedType = procform->amprocrighttype;
selectedFunc = procform->amproc;
}
}
ReleaseCatCacheList(proclist);
/*
* Throw error if needed. It seems worth taking the trouble to
* distinguish "no support at all" from "you didn't match any
* available offset type".
*/
if (nfuncs == 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("RANGE with offset PRECEDING/FOLLOWING is not supported for column type %s",
format_type_be(rangeopcintype)),
parser_errposition(pstate, exprLocation(node))));
if (nmatches == 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("RANGE with offset PRECEDING/FOLLOWING is not supported for column type %s and offset type %s",
format_type_be(rangeopcintype),
format_type_be(nodeType)),
errhint("Cast the offset value to an appropriate type."),
parser_errposition(pstate, exprLocation(node))));
if (nmatches != 1 && selectedType != preferredType)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("RANGE with offset PRECEDING/FOLLOWING has multiple interpretations for column type %s and offset type %s",
format_type_be(rangeopcintype),
format_type_be(nodeType)),
errhint("Cast the offset value to the exact intended type."),
parser_errposition(pstate, exprLocation(node))));
/* OK, coerce the offset to the right type */
constructName = "RANGE";
node = coerce_to_specific_type(pstate, node,
selectedType, constructName);
*inRangeFunc = selectedFunc;
}
else if (frameOptions & FRAMEOPTION_GROUPS)
{
/* Transform the raw expression tree */
node = transformExpr(pstate, clause, EXPR_KIND_WINDOW_FRAME_GROUPS);
/*
* Like LIMIT clause, simply coerce to int8
*/
constructName = "GROUPS";
node = coerce_to_specific_type(pstate, node, INT8OID, constructName);
}
else
{
Assert(false);
node = NULL;
}
/* Disallow variables in frame offsets */
checkExprIsVarFree(pstate, node, constructName);
return node;
}
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