1 files changed, 39 insertions, 2 deletions
diff --git a/src/test/regress/sql/union.sql b/src/test/regress/sql/union.sql
index 56bd20e741c..782cca23701 100644
--- a/src/test/regress/sql/union.sql
+++ b/src/test/regress/sql/union.sql
@@ -460,7 +460,7 @@ drop table events_child, events, other_events;
 reset enable_indexonlyscan;
 
 --
--- Test handling of UNION with provably empty inputs
+-- Test handling of UNION / EXCEPT / INTERSECT with provably empty inputs
 --
 
 -- Ensure the empty UNION input is pruned and de-duplication is done for the
@@ -484,7 +484,44 @@ SELECT two FROM tenk1 WHERE 1=2
 UNION
 SELECT four FROM tenk1 WHERE 1=2
 UNION
-SELECT ten FROM tenk1 WHERE 1=2;
+SELECT ten FROM tenk1 WHERE 1=2
+ORDER BY 1;
+
+-- Ensure the planner provides a const-false Result node
+EXPLAIN (COSTS OFF, VERBOSE)
+SELECT two FROM tenk1 WHERE 1=2
+INTERSECT
+SELECT four FROM tenk1
+ORDER BY 1;
+
+-- As above, with the inputs swapped
+EXPLAIN (COSTS OFF, VERBOSE)
+SELECT four FROM tenk1
+INTERSECT
+SELECT two FROM tenk1 WHERE 1=2
+ORDER BY 1;
+
+-- Try with both inputs dummy
+EXPLAIN (COSTS OFF, VERBOSE)
+SELECT four FROM tenk1 WHERE 1=2
+INTERSECT
+SELECT two FROM tenk1 WHERE 1=2
+ORDER BY 1;
+
+-- Ensure the planner provides a const-false Result node when the left input
+-- is empty
+EXPLAIN (COSTS OFF, VERBOSE)
+SELECT two FROM tenk1 WHERE 1=2
+EXCEPT
+SELECT four FROM tenk1
+ORDER BY 1;
+
+-- Ensure the planner only scans the left input when right input is empty
+EXPLAIN (COSTS OFF, VERBOSE)
+SELECT two FROM tenk1
+EXCEPT ALL
+SELECT four FROM tenk1 WHERE 1=2
+ORDER BY 1;
 
 -- Test constraint exclusion of UNION ALL subqueries
 explain (costs off)