Tweak findTargetlistEntry so that bare names occurring in GROUP BY clauses

tglsfdc · tglsfdc · commit b5e52b080c7b · 2004-04-18T18:12:58.000Z
are sought first as local FROM columns, then as local SELECT-list aliases,
and finally as outer FROM columns; the former behavior made outer FROM
columns take precedence over aliases.  This does not change spec
conformance because SQL99 allows only the first case anyway, and it seems
more useful and self-consistent.  Per gripe from Dennis Bjorklund 2004-04-05.
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_clause.c,v 1.127 2004/01/23 02:13:12 neilc Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_clause.c,v 1.128 2004/04/18 18:12:57 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1140,10 +1140,18 @@ findTargetlistEntry(ParseState *pstate, Node *node, List *tlist, int clause)
 			 * is a matching column.  If so, fall through to let
 			 * transformExpr() do the rest.  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
+			 * 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) != NULL)
+			if (colNameToVar(pstate, name, true) != NULL)
 				name = NULL;
 		}
 
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.168 2004/04/02 19:06:58 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.169 2004/04/18 18:12:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -966,7 +966,7 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
 				char	   *name = strVal(lfirst(cref->fields));
 
 				/* Try to identify as an unqualified column */
-				node = colnameToVar(pstate, name);
+				node = colNameToVar(pstate, name, false);
 
 				if (node == NULL)
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.93 2004/04/02 19:06:58 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.94 2004/04/18 18:12:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -531,13 +531,14 @@ scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte, char *colname)
 }
 
 /*
- * colnameToVar
+ * colNameToVar
  *	  Search for an unqualified column name.
  *	  If found, return the appropriate Var node (or expression).
  *	  If not found, return NULL.  If the name proves ambiguous, raise error.
+ *	  If localonly is true, only names in the innermost query are considered.
  */
 Node *
-colnameToVar(ParseState *pstate, char *colname)
+colNameToVar(ParseState *pstate, char *colname, bool localonly)
 {
 	Node	   *result = NULL;
 	ParseState *orig_pstate = pstate;
@@ -594,8 +595,8 @@ colnameToVar(ParseState *pstate, char *colname)
 			}
 		}
 
-		if (result != NULL)
-			break;				/* found */
+		if (result != NULL || localonly)
+			break;				/* found, or don't want to look at parent */
 
 		pstate = pstate->parentParseState;
 		levels_up++;
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_relation.h,v 1.43 2004/04/02 19:07:02 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_relation.h,v 1.44 2004/04/18 18:12:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -32,7 +32,7 @@ extern RangeTblEntry *GetRTEByRangeTablePosn(ParseState *pstate,
 											 int sublevels_up);
 extern Node *scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte,
 							  char *colname);
-extern Node *colnameToVar(ParseState *pstate, char *colname);
+extern Node *colNameToVar(ParseState *pstate, char *colname, bool localonly);
 extern Node *qualifiedNameToVar(ParseState *pstate,
 				   char *schemaname,
 				   char *refname,

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.168 2004/04/02 19:06:58 tgl Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.169 2004/04/18 18:12:58 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -966,7 +966,7 @@ transformColumnRef(ParseState pstate, ColumnRef cref)`
`966`	`966`	`char *name = strVal(lfirst(cref->fields));`
`967`	`967`
`968`	`968`	`/* Try to identify as an unqualified column */`
`969`		`- node = colnameToVar(pstate, name);`
	`969`	`+ node = colNameToVar(pstate, name, false);`
`970`	`970`
`971`	`971`	`if (node == NULL)`
`972`	`972`	`{`