Fix alias-for-target-table-of-UPDATE-or-DELETE patch so that alias can

be any ColId other than 'SET', rather than only IDENT as originally.
Per discussion.

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 22e20165b96aec1d3e3e71b4c9aff2c55ab62a49..82d36cea023bda50c1d9ba2b135ad6ff6aaa5b03 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.523 2006/01/22 05:20:33 neilc Exp $
+ *   $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.524 2006/01/22 20:03:16 tgl Exp $
  *
  * HISTORY
  *   AUTHOR            DATE            MAJOR EVENT
@@ -429,6 +429,7 @@ static void doNegateFloat(Value *v);
 %token   ICONST PARAM
 
 /* precedence: lowest to highest */
+%nonassoc  SET             /* see relation_expr_opt_alias */
 %left      UNION EXCEPT
 %left      INTERSECT
 %left      OR
@@ -5880,11 +5881,27 @@ relation_expr:
        ;
 
 
-relation_expr_opt_alias: relation_expr
+/*
+ * Given "UPDATE foo set set ...", we have to decide without looking any
+ * further ahead whether the first "set" is an alias or the UPDATE's SET
+ * keyword.  Since "set" is allowed as a column name both interpretations
+ * are feasible.  We resolve the shift/reduce conflict by giving the first
+ * relation_expr_opt_alias production a higher precedence than the SET token
+ * has, causing the parser to prefer to reduce, in effect assuming that the
+ * SET is not an alias.
+ */
+relation_expr_opt_alias: relation_expr                 %prec UMINUS
                {
                    $$ = $1;
                }
-           | relation_expr opt_as IDENT
+           | relation_expr ColId
+               {
+                   Alias *alias = makeNode(Alias);
+                   alias->aliasname = $2;
+                   $1->alias = alias;
+                   $$ = $1;
+               }
+           | relation_expr AS ColId
                {
                    Alias *alias = makeNode(Alias);
                    alias->aliasname = $3;
@@ -6827,7 +6844,7 @@ a_expr:       c_expr                                  { $$ = $1; }
                        $$ = (Node *) makeSimpleA_Expr(AEXPR_IN, "<>", $1, $4);
                    }
                }
-           | a_expr subquery_Op sub_type select_with_parens %prec Op
+           | a_expr subquery_Op sub_type select_with_parens    %prec Op
                {
                    SubLink *n = makeNode(SubLink);
                    n->subLinkType = $3;
@@ -6836,14 +6853,14 @@ a_expr:     c_expr                                  { $$ = $1; }
                    n->subselect = $4;
                    $$ = (Node *)n;
                }
-           | a_expr subquery_Op sub_type '(' a_expr ')' %prec Op
+           | a_expr subquery_Op sub_type '(' a_expr ')'        %prec Op
                {
                    if ($3 == ANY_SUBLINK)
                        $$ = (Node *) makeA_Expr(AEXPR_OP_ANY, $2, $1, $5);
                    else
                        $$ = (Node *) makeA_Expr(AEXPR_OP_ALL, $2, $1, $5);
                }
-           | UNIQUE select_with_parens %prec Op
+           | UNIQUE select_with_parens
                {
                    /* Not sure how to get rid of the parentheses
                     * but there are lots of shift/reduce errors without them.
@@ -6901,7 +6918,7 @@ b_expr:       c_expr
                { $$ = (Node *) makeA_Expr(AEXPR_OP, $1, NULL, $2); }
            | b_expr qual_Op                    %prec POSTFIXOP
                { $$ = (Node *) makeA_Expr(AEXPR_OP, $2, $1, NULL); }
-           | b_expr IS DISTINCT FROM b_expr    %prec IS
+           | b_expr IS DISTINCT FROM b_expr        %prec IS
                {
                    $$ = (Node *) makeSimpleA_Expr(AEXPR_DISTINCT, "=", $1, $5);
                }
@@ -6910,7 +6927,7 @@ b_expr:       c_expr
                    $$ = (Node *) makeA_Expr(AEXPR_NOT, NIL,
                        NULL, (Node *) makeSimpleA_Expr(AEXPR_DISTINCT, "=", $1, $6));
                }
-           | b_expr IS OF '(' type_list ')'    %prec IS
+           | b_expr IS OF '(' type_list ')'        %prec IS
                {
                    $$ = (Node *) makeSimpleA_Expr(AEXPR_OF, "=", $1, (Node *) $5);
                }