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Implement the FILTER clause for aggregate function calls.

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This is SQL-standard with a few extensions, namely support for
subqueries and outer references in clause expressions.

catversion bump due to change in Aggref and WindowFunc.

David Fetter, reviewed by Dean Rasheed.
This commit is contained in:
Noah Misch
2013-07-16 20:15:36 -04:00
parent 7a8e9f298e
commit b560ec1b0d
35 changed files with 403 additions and 51 deletions
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30
src/backend/parser/parse_func.c
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@ -56,13 +56,13 @@ static Node *ParseComplexProjection(ParseState *pstate, char *funcname,
* Also, when is_column is true, we return NULL on failure rather than
* reporting a no-such-function error.
*
* The argument expressions (in fargs) must have been transformed already.
* But the agg_order expressions, if any, have not been.
* The argument expressions (in fargs) and filter must have been transformed
* already. But the agg_order expressions, if any, have not been.
*/
Node *
ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
List *agg_order, bool agg_star, bool agg_distinct,
bool func_variadic,
List *agg_order, Expr *agg_filter,
bool agg_star, bool agg_distinct, bool func_variadic,
WindowDef *over, bool is_column, int location)
{
Oid rettype;
@ -174,8 +174,8 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
* the "function call" could be a projection. We also check that there
* wasn't any aggregate or variadic decoration, nor an argument name.
*/
if (nargs == 1 && agg_order == NIL && !agg_star && !agg_distinct &&
over == NULL && !func_variadic && argnames == NIL &&
if (nargs == 1 && agg_order == NIL && agg_filter == NULL && !agg_star &&
!agg_distinct && over == NULL && !func_variadic && argnames == NIL &&
list_length(funcname) == 1)
{
Oid argtype = actual_arg_types[0];
@ -251,6 +251,12 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
errmsg("ORDER BY specified, but %s is not an aggregate function",
NameListToString(funcname)),
parser_errposition(pstate, location)));
if (agg_filter)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("FILTER specified, but %s is not an aggregate function",
NameListToString(funcname)),
parser_errposition(pstate, location)));
if (over)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
@ -402,6 +408,7 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
/* aggcollid and inputcollid will be set by parse_collate.c */
/* args, aggorder, aggdistinct will be set by transformAggregateCall */
aggref->aggstar = agg_star;
aggref->aggfilter = agg_filter;
/* agglevelsup will be set by transformAggregateCall */
aggref->location = location;
@ -460,6 +467,7 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
/* winref will be set by transformWindowFuncCall */
wfunc->winstar = agg_star;
wfunc->winagg = (fdresult == FUNCDETAIL_AGGREGATE);
wfunc->aggfilter = agg_filter;
wfunc->location = location;
/*
@ -482,6 +490,16 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
NameListToString(funcname)),
parser_errposition(pstate, location)));
/*
* Reject window functions which are not aggregates in the case of
* FILTER.
*/
if (!wfunc->winagg && agg_filter)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("FILTER is not implemented in non-aggregate window functions"),
parser_errposition(pstate, location)));
/*
* ordered aggs not allowed in windows yet
*/