Generate a reasonable error message when an aggregate function is applied

to an undecorated relation name (cf. example from Ed Loehr, 5/25/00).

diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c
index 3b543c3..ed6a910 100644 (file)
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.78 2000/04/12 17:15:26 momjian Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.79 2000/05/26 03:56:40 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -271,6 +271,7 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
        Node       *retval;
        bool            retset;
        bool            must_be_agg = agg_star || agg_distinct;
+       bool            could_be_agg;
        bool            attisset = false;
        Oid                     toid = InvalidOid;
        Expr       *expr;
@@ -291,7 +292,7 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
        if (nargs == 1 && !must_be_agg)
        {
                /* Is it a plain Relation name from the parser? */
-               if (IsA(first_arg, Ident) &&((Ident *) first_arg)->isRel)
+               if (IsA(first_arg, Ident) && ((Ident *) first_arg)->isRel)
                {
                        Ident      *ident = (Ident *) first_arg;
                        RangeTblEntry *rte;
@@ -413,28 +414,31 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
                }
        }
 
-       if (nargs == 1 || must_be_agg)
+       /*
+        * See if it's an aggregate.
+        */
+       if (must_be_agg)
        {
-
-               /*
-                * See if it's an aggregate.
-                */
-               Oid                     basetype;
-               int                     ncandidates;
-               CandidateList candidates;
-
                /* We don't presently cope with, eg, foo(DISTINCT x,y) */
                if (nargs != 1)
                        elog(ERROR, "Aggregate functions may only have one parameter");
+               /* Agg's argument can't be a relation name, either */
+               if (IsA(first_arg, Ident) && ((Ident *) first_arg)->isRel)
+                       elog(ERROR, "Aggregate functions cannot be applied to relation names");
+               could_be_agg = true;
+       }
+       else
+       {
+               /* Try to parse as an aggregate if above-mentioned checks are OK */
+               could_be_agg = (nargs == 1) &&
+                       !(IsA(first_arg, Ident) && ((Ident *) first_arg)->isRel);
+       }
 
-               /*
-                * the aggregate COUNT is a special case, ignore its base type.
-                * Treat it as zero.   XXX mighty ugly --- FIXME
-                */
-               if (strcmp(funcname, "count") == 0)
-                       basetype = 0;
-               else
-                       basetype = exprType(lfirst(fargs));
+       if (could_be_agg)
+       {
+               Oid                     basetype = exprType(lfirst(fargs));
+               int                     ncandidates;
+               CandidateList candidates;
 
                /* try for exact match first... */
                if (SearchSysCacheTuple(AGGNAME,
@@ -445,9 +449,18 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
                                                                         fargs, agg_star, agg_distinct,
                                                                         precedence);
 
+               /* check for aggregate-that-accepts-any-type (eg, COUNT) */
+               if (SearchSysCacheTuple(AGGNAME,
+                                                               PointerGetDatum(funcname),
+                                                               ObjectIdGetDatum(0),
+                                                               0, 0))
+                       return (Node *) ParseAgg(pstate, funcname, 0,
+                                                                        fargs, agg_star, agg_distinct,
+                                                                        precedence);
+
                /*
                 * No exact match yet, so see if there is another entry in the
-                * aggregate table which is compatible. - thomas 1998-12-05
+                * aggregate table that is compatible. - thomas 1998-12-05
                 */
                ncandidates = agg_get_candidates(funcname, basetype, &candidates);
                if (ncandidates > 0)
@@ -497,7 +510,7 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
        {
                Node       *arg = lfirst(i);
 
-               if (IsA(arg, Ident) &&((Ident *) arg)->isRel)
+               if (IsA(arg, Ident) && ((Ident *) arg)->isRel)
                {
                        RangeTblEntry *rte;
                        int                     vnum;