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Diffstat (limited to 'src/backend/optimizer/util/clauses.c')
| -rw-r--r-- | src/backend/optimizer/util/clauses.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index 26a3e050086..f45131c34c5 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -3333,6 +3333,13 @@ eval_const_expressions_mutator(Node *node, -1, coalesceexpr->coalescecollid); + /* + * If there's exactly one surviving argument, we no longer + * need COALESCE at all: the result is that argument + */ + if (list_length(newargs) == 1) + return (Node *) linitial(newargs); + newcoalesce = makeNode(CoalesceExpr); newcoalesce->coalescetype = coalesceexpr->coalescetype; newcoalesce->coalescecollid = coalesceexpr->coalescecollid; |