BUG#912538: Wrong result (missing rows) with semijoin=on, firstmatch=on, ...

- setup_semijoin_dups_elimination() would incorrectly set join_tab->do_firstmatch 
  when the join order had outer tables interleaved with inner.

1 files changed, 14 insertions, 0 deletions

diff --git a/mysql-test/t/subselect_sj2.test b/mysql-test/t/subselect_sj2.test
index 9a664ee9881..30dc20087d1 100644
--- a/mysql-test/t/subselect_sj2.test
+++ b/mysql-test/t/subselect_sj2.test
@@ -1076,5 +1076,19 @@ SELECT * FROM t3 LEFT JOIN (v1,t2) ON t3.a = t2.a
 DROP VIEW v1;
 DROP TABLE t1,t2,t3,t4;
 
+--echo #
+--echo # BUG#912538: Wrong result (missing rows) with semijoin=on, firstmatch=on, ...
+--echo #
+CREATE TABLE t1 ( a INT NOT NULL, UNIQUE KEY(a) );
+INSERT INTO t1 VALUES (1),(2),(3),(4);
+
+# t2 needs to be InnoDB
+CREATE TABLE t2 ( b INT, c INT ) ENGINE=InnoDB;
+INSERT INTO t2 VALUES (1,1);
+
+SELECT * FROM t1, t2 WHERE c IN (SELECT c FROM t1, t2 WHERE a = b);
+
+DROP TABLE t1,t2;
+
 --echo # This must be the last in the file:
 set optimizer_switch=@subselect_sj2_tmp;