Fixed bug #28571. Outer join queries with ON conditions over

constant outer tables did not return null complemented
rows when conditions were evaluated to FALSE.
Wrong results were returned because the conditions over constant
outer tables, when being pushed down, were erroneously enclosed 
into the guard function used for WHERE conditions.


mysql-test/r/join_outer.result:
  Added a test case for bug #28571.
mysql-test/t/join_outer.test:
  Added a test case for bug #28571.
sql/sql_select.cc:
  Fixed bug #28571. Outer join queries with ON conditions over
  constant outer tables did not return null complemented
  rows when conditions were evaluated to FALSE.
  Wrong results were returned because the conditions over constant
  outer tables, when being pushed down, were erroneously enclosed 
  into the guard function used for WHERE conditions.
  The problem is fixed in the function make_join_select. Now the
  conditions over constant tables from ON expressions are pushed
  down after the conditions from WHERE has been pushed down.

1 files changed, 16 insertions, 0 deletions

diff --git a/mysql-test/t/join_outer.test b/mysql-test/t/join_outer.test
index 51e79a20d65..1a59dbf8fc2 100644
--- a/mysql-test/t/join_outer.test
+++ b/mysql-test/t/join_outer.test
@@ -845,3 +845,19 @@ SELECT t1.id, a FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.b IS NULL;
 show status like 'Handler_read%';
 
 DROP TABLE t1,t2;
+
+#
+# Bug 28571: outer join with false on condition over constant tables 
+#
+
+CREATE TABLE t1 (c int  PRIMARY KEY, e int NOT NULL);
+INSERT INTO t1 VALUES (1,0), (2,1);
+CREATE TABLE t2 (d int PRIMARY KEY);
+INSERT INTO t2 VALUES (1), (2), (3);
+
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
+SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
+SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d<=>NULL;
+
+DROP TABLE t1,t2;
+