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postgres/src/backend/parser/parse_clause.c
Tom Lane 382ceffdf7 Phase 3 of pgindent updates. 
Don't move parenthesized lines to the left, even if that means they
flow past the right margin.

By default, BSD indent lines up statement continuation lines that are
within parentheses so that they start just to the right of the preceding
left parenthesis.  However, traditionally, if that resulted in the
continuation line extending to the right of the desired right margin,
then indent would push it left just far enough to not overrun the margin,
if it could do so without making the continuation line start to the left of
the current statement indent.  That makes for a weird mix of indentations
unless one has been completely rigid about never violating the 80-column
limit.

This behavior has been pretty universally panned by Postgres developers.
Hence, disable it with indent's new -lpl switch, so that parenthesized
lines are always lined up with the preceding left paren.

This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.

Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
2017-06-21 15:35:54 -04:00

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/*-------------------------------------------------------------------------
*
* parse_clause.c
* handle clauses in parser
*
* Portions Copyright (c) 1996-2017, 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 "miscadmin.h"
#include "access/heapam.h"
#include "access/tsmapi.h"
#include "catalog/catalog.h"
#include "catalog/heap.h"
#include "catalog/pg_am.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_constraint_fn.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/tlist.h"
#include "optimizer/var.h"
#include "parser/analyze.h"
#include "parser/parsetree.h"
#include "parser/parser.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 "rewrite/rewriteManip.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
/* Convenience macro for the most common makeNamespaceItem() case */
#define makeDefaultNSItem(rte) makeNamespaceItem(rte, 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 *transformCTEReference(ParseState *pstate, RangeVar *r,
CommonTableExpr *cte, Index levelsup);
static RangeTblEntry *transformENRReference(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,
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,
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;
/* So far special relations are immutable; so they cannot be targets. */
rte = getRTEForSpecialRelationTypes(pstate, relation);
if (rte != NULL)
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)
heap_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 heap_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,
relation->alias, inh, false);
pstate->p_target_rangetblentry = rte;
/* assume new rte is at end */
rtindex = list_length(pstate->p_rtable);
Assert(rte == rt_fetch(rtindex, pstate->p_rtable));
/*
* 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;
}
/*
* Given a relation-options list (of DefElems), return true iff the specified
* table/result set should be created with OIDs. This needs to be done after
* parsing the query string because the return value can depend upon the
* default_with_oids GUC var.
*
* In some situations, we want to reject an OIDS option even if it's present.
* That's (rather messily) handled here rather than reloptions.c, because that
* code explicitly punts checking for oids to here.
*/
bool
interpretOidsOption(List *defList, bool allowOids)
{
ListCell *cell;
/* Scan list to see if OIDS was included */
foreach(cell, defList)
{
DefElem *def = (DefElem *) lfirst(cell);
if (def->defnamespace == NULL &&
pg_strcasecmp(def->defname, "oids") == 0)
{
if (!allowOids)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("unrecognized parameter \"%s\"",
def->defname)));
return defGetBoolean(def);
}
}
/* Force no-OIDS result if caller disallows OIDS. */
if (!allowOids)
return false;
/* OIDS option was not specified, so use default. */
return default_with_oids;
}
/*
* 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;
}
/*
* transformCTEReference --- transform a RangeVar that references a common
* table expression (ie, a sub-SELECT defined in a WITH clause)
*/
static RangeTblEntry *
transformCTEReference(ParseState *pstate, RangeVar *r,
CommonTableExpr *cte, Index levelsup)
{
RangeTblEntry *rte;
rte = addRangeTableEntryForCTE(pstate, cte, levelsup, r, true);
return rte;
}
/*
* transformENRReference --- transform a RangeVar that references an ephemeral
* named relation
*/
static RangeTblEntry *
transformENRReference(ParseState *pstate, RangeVar *r)
{
RangeTblEntry *rte;
rte = addRangeTableEntryForENR(pstate, r, 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;
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,
type_is_collatable(typid) ? DEFAULT_COLLATION_OID : InvalidOid);
/* 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)
{
char *name = strVal(lfirst(lc2));
if (name == NULL)
continue;
if (strcmp(name, r->name) == 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("namespace name \"%s\" is not unique",
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;
}
/* Note the string may be NULL */
ns_names = lappend(ns_names, makeString(r->name));
}
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;
}
static RangeTblEntry *
getRTEForSpecialRelationTypes(ParseState *pstate, RangeVar *rv)
{
CommonTableExpr *cte;
Index levelsup;
RangeTblEntry *rte = NULL;
cte = scanNameSpaceForCTE(pstate, rv->relname, &levelsup);
if (cte)
rte = transformCTEReference(pstate, rv, cte, levelsup);
if (!rte && scanNameSpaceForENR(pstate, rv->relname))
rte = transformENRReference(pstate, rv);
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 = NULL;
int rtindex;
/*
* if it is an unqualified name, it might be a CTE or tuplestore
* reference
*/
if (!rv->schemaname)
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));
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));
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));
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));
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().
*
* NB: this coding relies on the fact that list_concat is not
* destructive to its second argument.
*/
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->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, 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_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;
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;
/* Process frame offset expressions */
wc->startOffset = transformFrameOffset(pstate, wc->frameOptions,
windef->startOffset);
wc->endOffset = transformFrameOffset(pstate, wc->frameOptions,
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() should have already rejected subqueries,
* aggregates, and window functions, based on the EXPR_KIND_ for an
* index expression. Expressions returning sets won't have been
* rejected, but don't bother doing so here; there should be no
* available expression unique index to match any such expression
* against 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 (infer->conname)
*constraint = get_relation_constraint_oid(RelationGetRelid(pstate->p_target_relation),
infer->conname, false);
}
/*
* 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
*/
static Node *
transformFrameOffset(ParseState *pstate, int frameOptions, Node *clause)
{
const char *constructName = NULL;
Node *node;
/* 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)
{
/* Transform the raw expression tree */
node = transformExpr(pstate, clause, EXPR_KIND_WINDOW_FRAME_RANGE);
/*
* this needs a lot of thought to decide how to support in the context
* of Postgres' extensible datatype framework
*/
constructName = "RANGE";
/* error was already thrown by gram.y, this is just a backstop */
elog(ERROR, "window frame with value offset is not implemented");
}
else
{
Assert(false);
node = NULL;
}
/* Disallow variables in frame offsets */
checkExprIsVarFree(pstate, node, constructName);
return node;
}
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