postgres/src/include/parser/parse_clause.h
Tom Lane 8d65da1f01 Support ordered-set (WITHIN GROUP) aggregates.
This patch introduces generic support for ordered-set and hypothetical-set
aggregate functions, as well as implementations of the instances defined in
SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(),
percent_rank(), cume_dist()).  We also added mode() though it is not in the
spec, as well as versions of percentile_cont() and percentile_disc() that
can compute multiple percentile values in one pass over the data.

Unlike the original submission, this patch puts full control of the sorting
process in the hands of the aggregate's support functions.  To allow the
support functions to find out how they're supposed to sort, a new API
function AggGetAggref() is added to nodeAgg.c.  This allows retrieval of
the aggregate call's Aggref node, which may have other uses beyond the
immediate need.  There is also support for ordered-set aggregates to
install cleanup callback functions, so that they can be sure that
infrastructure such as tuplesort objects gets cleaned up.

In passing, make some fixes in the recently-added support for variadic
aggregates, and make some editorial adjustments in the recent FILTER
additions for aggregates.  Also, simplify use of IsBinaryCoercible() by
allowing it to succeed whenever the target type is ANY or ANYELEMENT.
It was inconsistent that it dealt with other polymorphic target types
but not these.

Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing,
and rather heavily editorialized upon by Tom Lane
2013-12-23 16:11:35 -05:00

52 lines
2.0 KiB
C

/*-------------------------------------------------------------------------
*
* parse_clause.h
* handle clauses in parser
*
*
* Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/parser/parse_clause.h
*
*-------------------------------------------------------------------------
*/
#ifndef PARSE_CLAUSE_H
#define PARSE_CLAUSE_H
#include "parser/parse_node.h"
extern void transformFromClause(ParseState *pstate, List *frmList);
extern int setTargetTable(ParseState *pstate, RangeVar *relation,
bool inh, bool alsoSource, AclMode requiredPerms);
extern bool interpretInhOption(InhOption inhOpt);
extern bool interpretOidsOption(List *defList, bool allowOids);
extern Node *transformWhereClause(ParseState *pstate, Node *clause,
ParseExprKind exprKind, const char *constructName);
extern Node *transformLimitClause(ParseState *pstate, Node *clause,
ParseExprKind exprKind, const char *constructName);
extern List *transformGroupClause(ParseState *pstate, List *grouplist,
List **targetlist, List *sortClause,
ParseExprKind exprKind, bool useSQL99);
extern List *transformSortClause(ParseState *pstate, List *orderlist,
List **targetlist, ParseExprKind exprKind,
bool resolveUnknown, bool useSQL99);
extern List *transformWindowDefinitions(ParseState *pstate,
List *windowdefs,
List **targetlist);
extern List *transformDistinctClause(ParseState *pstate,
List **targetlist, List *sortClause, bool is_agg);
extern List *transformDistinctOnClause(ParseState *pstate, List *distinctlist,
List **targetlist, List *sortClause);
extern List *addTargetToSortList(ParseState *pstate, TargetEntry *tle,
List *sortlist, List *targetlist, SortBy *sortby,
bool resolveUnknown);
extern Index assignSortGroupRef(TargetEntry *tle, List *tlist);
extern bool targetIsInSortList(TargetEntry *tle, Oid sortop, List *sortList);
#endif /* PARSE_CLAUSE_H */