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8 | 8 | * |
9 | 9 | * |
10 | 10 | * IDENTIFICATION |
11 | | - * $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.193 2005/04/06 16:34:06 tgl Exp $ |
| 11 | + * $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.194 2005/04/10 20:57:32 tgl Exp $ |
12 | 12 | * |
13 | 13 | * HISTORY |
14 | 14 | * AUTHORDATEMAJOR EVENT |
@@ -1788,6 +1788,10 @@ eval_const_expressions_mutator(Node *node, |
1788 | 1788 | newargs=lappend(newargs,e); |
1789 | 1789 | } |
1790 | 1790 |
|
| 1791 | +/* If all the arguments were constant null, the result is just null */ |
| 1792 | +if (newargs==NIL) |
| 1793 | +return (Node*)makeNullConst(coalesceexpr->coalescetype); |
| 1794 | + |
1791 | 1795 | newcoalesce=makeNode(CoalesceExpr); |
1792 | 1796 | newcoalesce->coalescetype=coalesceexpr->coalescetype; |
1793 | 1797 | newcoalesce->args=newargs; |
|