Repair list-vs-node confusion that resulted in failure for INNER JOIN ON.

Make it behave correctly when there are more than two tables being
joined, also.  Update regression test expected outputs.

src/backend/parser/parse_clause.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_clause.c,v 1.59 2000/04/12 17:15:26 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_clause.c,v 1.60 2000/05/12 01:33:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -41,8 +41,8 @@ static List *addTargetToSortList(TargetEntry *tle, List *sortlist,
 static bool exprIsInSortList(Node *expr, List *sortList, List *targetList);
 
 #ifndef DISABLE_OUTER_JOINS
-static Node *transformUsingClause(ParseState *pstate, List *using, List *left, List *right);
-
+static List *transformUsingClause(ParseState *pstate, List *using,
+								  List *left, List *right);
 #endif
 
 
@@ -94,32 +94,33 @@ setTargetTable(ParseState *pstate, char *relname)
 }
 
 
-Node *
-			mergeInnerJoinQuals(ParseState *pstate, Node *clause);
-
-Node *
+static Node *
 mergeInnerJoinQuals(ParseState *pstate, Node *clause)
 {
-	A_Expr	   *expr = (A_Expr *) pstate->p_join_quals;
+	List	   *jquals;
 
-	if (expr == NULL)
-		return clause;
+	foreach(jquals, pstate->p_join_quals)
+	{
+		Node	   *jqual = (Node *) lfirst(jquals);
 
-	if (clause != NULL)
+		if (clause == NULL)
+			clause = jqual;
+		else
 		{
 			A_Expr	   *a = makeNode(A_Expr);
 
 			a->oper = AND;
 			a->opname = NULL;
-		a->lexpr = (Node *) expr;
-		a->rexpr = clause;
-		expr = a;
+			a->lexpr = clause;
+			a->rexpr = jqual;
+			clause = (Node *) a;
+		}
 	}
 
-	/* Make sure that we don't do this twice... */
-	pstate->p_join_quals = NULL;
+	/* Make sure that we don't add same quals twice... */
+	pstate->p_join_quals = NIL;
 
-	return (Node *) expr;
+	return clause;
 }	/* mergeInnerJoinQuals() */
 
 /*
@@ -131,7 +132,7 @@ transformWhereClause(ParseState *pstate, Node *clause)
 {
 	Node	   *qual;
 
-	if (pstate->p_join_quals != NULL)
+	if (pstate->p_join_quals != NIL)
 		clause = mergeInnerJoinQuals(pstate, clause);
 
 	if (clause == NULL)
@@ -275,21 +276,22 @@ ExpandAttrs(Attr *attr)
 
 /* transformUsingClause()
  * Take an ON or USING clause from a join expression and expand if necessary.
+ * Result is an implicitly-ANDed list of untransformed qualification clauses.
  */
-static Node *
-transformUsingClause(ParseState *pstate, List *usingList, List *leftList, List *rightList)
+static List *
+transformUsingClause(ParseState *pstate, List *usingList,
+					 List *leftList, List *rightList)
 {
-	A_Expr	   *expr = NULL;
+	List	   *result = NIL;
 	List	   *using;
 
 	foreach(using, usingList)
 	{
-		List	   *col;
-		A_Expr	   *e;
-
 		Attr	   *uattr = lfirst(using);
 		Attr	   *lattr = NULL,
 				   *rattr = NULL;
+		List	   *col;
+		A_Expr	   *e;
 
 		/*
 		 * find the first instances of this column in the shape list and
@@ -324,22 +326,11 @@ transformUsingClause(ParseState *pstate, List *usingList, List *leftList, List *
 		e->lexpr = (Node *) lattr;
 		e->rexpr = (Node *) rattr;
 
-		if (expr != NULL)
-		{
-			A_Expr	   *a = makeNode(A_Expr);
-
-			a->oper = AND;
-			a->opname = NULL;
-			a->lexpr = (Node *) expr;
-			a->rexpr = (Node *) e;
-			expr = a;
-		}
-		else
-			expr = e;
+		result = lappend(result, e);
 	}
 
-	return ((Node *) transformExpr(pstate, (Node *) expr, EXPR_COLUMN_FIRST));
-}	/* transformUsiongClause() */
+	return result;
+}	/* transformUsingClause() */
 
 #endif
 
@@ -632,7 +623,7 @@ parseFromClause(ParseState *pstate, List *frmList)
 
 					printf("JOIN/USING input quals are %s\n", nodeToString(j->quals));
 
-					j->quals = (List *) transformUsingClause(pstate, shape, l_cols, r_cols);
+					j->quals = transformUsingClause(pstate, shape, l_cols, r_cols);
 
 					printf("JOIN/USING transformed quals are %s\n", nodeToString(j->quals));
 
@@ -650,7 +641,12 @@ parseFromClause(ParseState *pstate, List *frmList)
 				else
 					j->quals = (List *) lcons(j->quals, NIL);
 
-				pstate->p_join_quals = (Node *) j->quals;
+				/* listCopy may not be needed here --- will j->quals list
+				 * be used again anywhere?  The #ifdef'd code below may need
+				 * it, if it ever gets used...
+				 */
+				pstate->p_join_quals = nconc(pstate->p_join_quals,
+											 listCopy(j->quals));
 
 #if 0
 				if (qual == NULL)
@@ -660,11 +656,13 @@ parseFromClause(ParseState *pstate, List *frmList)
 #endif
 
 #if 0
+				/* XXX this code is WRONG because j->quals is a List
+				 * not a simple expression.  Perhaps *qual
+				 * ought also to be a List and we append to it,
+				 * similarly to the way p_join_quals is handled above?
+				 */
 				if (*qual == NULL)
 				{
-#endif
-
-#if 0
 					/* merge qualified join clauses... */
 					if (j->quals != NULL)
 					{
@@ -682,9 +680,6 @@ parseFromClause(ParseState *pstate, List *frmList)
 						else
 							*qual = (Node *) j->quals;
 					}
-#endif
-
-#if 0
 				}
 				else
 				{

src/include/parser/parse_node.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: parse_node.h,v 1.19 2000/04/12 17:16:45 momjian Exp $
+ * $Id: parse_node.h,v 1.20 2000/05/12 01:33:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -17,9 +17,10 @@
 #include "utils/rel.h"
 
 /* State information used during parse analysis
- * p_join_quals is a list of qualification expressions
- * found in the FROM clause. Needs to be available later
- * to merge with other qualifiers from the WHERE clause.
+ * p_join_quals is a list of untransformed qualification expressions
+ * (implicitly ANDed together) found in the FROM clause.
+ * Needs to be available later to merge with other qualifiers from the
+ * WHERE clause.
  */
 typedef struct ParseState
 {
@@ -36,7 +37,7 @@ typedef struct ParseState
 	RangeTblEntry *p_target_rangetblentry;
 	List	   *p_shape;
 	List	   *p_alias;
-	Node	   *p_join_quals;
+	List	   *p_join_quals;
 } ParseState;
 
 extern ParseState *make_parsestate(ParseState *parentParseState);

src/test/regress/expected/join.out

@@ -274,10 +274,22 @@ SELECT '' AS "xxx", *
 --
 SELECT '' AS "xxx", *
   FROM J1_TBL JOIN J2_TBL ON (J1_TBL.i = J2_TBL.i);
-ERROR:  transformExpr: does not know how to transform node 501 (internal error)
+ xxx | i | j |   t   | i | k  
+-----+---+---+-------+---+----
+     | 1 | 3 | one   | 1 | -1
+     | 2 | 2 | two   | 2 |  2
+     | 2 | 2 | two   | 2 |  4
+     | 3 | 1 | three | 3 | -3
+(4 rows)
+
 SELECT '' AS "xxx", *
   FROM J1_TBL JOIN J2_TBL ON (J1_TBL.i = J2_TBL.k);
-ERROR:  transformExpr: does not know how to transform node 501 (internal error)
+ xxx | i | j |  t   | i | k 
+-----+---+---+------+---+---
+     | 2 | 2 | two  | 2 | 2
+     | 4 | 0 | four | 2 | 4
+(2 rows)
+
 SELECT '' AS "xxx", *
   FROM J1_TBL CROSS JOIN J2_TBL;
  xxx | i | j |   t   | i | k  
@@ -305,7 +317,16 @@ SELECT '' AS "xxx", *
 --
 SELECT '' AS "xxx", *
   FROM J1_TBL JOIN J2_TBL ON (J1_TBL.i <= J2_TBL.k);
-ERROR:  transformExpr: does not know how to transform node 501 (internal error)
+ xxx | i | j |   t   | i | k 
+-----+---+---+-------+---+---
+     | 1 | 3 | one   | 2 | 2
+     | 2 | 2 | two   | 2 | 2
+     | 1 | 3 | one   | 2 | 4
+     | 2 | 2 | two   | 2 | 4
+     | 3 | 1 | three | 2 | 4
+     | 4 | 0 | four  | 2 | 4
+(6 rows)
+
 --
 -- Outer joins
 --