1 files changed, 29 insertions, 0 deletions
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 75fff9bad04..4c653f24736 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -408,6 +408,35 @@ EXPLAIN (VERBOSE, COSTS OFF)
   SELECT * FROM ft1 t1 WHERE t1.c1 === t1.c2 order by t1.c2 limit 1;
 SELECT * FROM ft1 t1 WHERE t1.c1 === t1.c2 order by t1.c2 limit 1;
 
+-- Test CASE pushdown
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT c1,c2,c3 FROM ft2 WHERE CASE WHEN c1 > 990 THEN c1 END < 1000 ORDER BY c1;
+SELECT c1,c2,c3 FROM ft2 WHERE CASE WHEN c1 > 990 THEN c1 END < 1000 ORDER BY c1;
+
+-- Nested CASE
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT c1,c2,c3 FROM ft2 WHERE CASE CASE WHEN c2 > 0 THEN c2 END WHEN 100 THEN 601 WHEN c2 THEN c2 ELSE 0 END > 600 ORDER BY c1;
+
+SELECT c1,c2,c3 FROM ft2 WHERE CASE CASE WHEN c2 > 0 THEN c2 END WHEN 100 THEN 601 WHEN c2 THEN c2 ELSE 0 END > 600 ORDER BY c1;
+
+-- CASE arg WHEN
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE c1 > (CASE mod(c1, 4) WHEN 0 THEN 1 WHEN 2 THEN 50 ELSE 100 END);
+
+-- CASE cannot be pushed down because of unshippable arg clause
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE c1 > (CASE random()::integer WHEN 0 THEN 1 WHEN 2 THEN 50 ELSE 100 END);
+
+-- these are shippable
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE CASE c6 WHEN 'foo' THEN true ELSE c3 < 'bar' END;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE CASE c3 WHEN c6 THEN true ELSE c3 < 'bar' END;
+
+-- but this is not because of collation
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE CASE c3 COLLATE "C" WHEN c6 THEN true ELSE c3 < 'bar' END;
+
 -- ===================================================================
 -- JOIN queries
 -- ===================================================================