BUG#901032: Wrong result for MIN/MAX on an indexed column with materialization and semijoin

- opt_sum_query() should not assume that join tables from sj-materialization
  have known numbers of rows.

mysql-test/r/subselect_mat.result

@@ -1728,6 +1728,19 @@ FROM t4 , t5
 );
 f1	f5
 DROP TABLE t1, t2, t3, t4, t5;
+#
+# BUG#901032: Wrong result for MIN/MAX on an indexed column with materialization and semijoin
+#
+CREATE TABLE t1 ( a INT, KEY(a) );
+INSERT INTO t1 VALUES (1);
+CREATE TABLE t2 ( b INT );
+INSERT INTO t2 VALUES (2);
+CREATE TABLE t3 ( c INT );
+INSERT INTO t3 VALUES (2);
+SELECT MIN(a) FROM t1, t2 WHERE b IN (SELECT c FROM t3 GROUP BY c);
+MIN(a)
+1
+DROP TABLE t1,t2,t3;
 # This must be at the end:
 set optimizer_switch=@subselect_sj_mat_tmp;
 set @subselect_mat_test_optimizer_switch_value=null;

mysql-test/r/subselect_sj_mat.result

@@ -1764,5 +1764,18 @@ FROM t4 , t5
 );
 f1	f5
 DROP TABLE t1, t2, t3, t4, t5;
+#
+# BUG#901032: Wrong result for MIN/MAX on an indexed column with materialization and semijoin
+#
+CREATE TABLE t1 ( a INT, KEY(a) );
+INSERT INTO t1 VALUES (1);
+CREATE TABLE t2 ( b INT );
+INSERT INTO t2 VALUES (2);
+CREATE TABLE t3 ( c INT );
+INSERT INTO t3 VALUES (2);
+SELECT MIN(a) FROM t1, t2 WHERE b IN (SELECT c FROM t3 GROUP BY c);
+MIN(a)
+1
+DROP TABLE t1,t2,t3;
 # This must be at the end:
 set optimizer_switch=@subselect_sj_mat_tmp;

mysql-test/t/subselect_sj_mat.test

@@ -1428,6 +1428,19 @@ ON ( t2.f5 ) IN (
 
 DROP TABLE t1, t2, t3, t4, t5;
 
+--echo #
+--echo # BUG#901032: Wrong result for MIN/MAX on an indexed column with materialization and semijoin
+--echo #
+CREATE TABLE t1 ( a INT, KEY(a) );
+INSERT INTO t1 VALUES (1);
+CREATE TABLE t2 ( b INT );
+INSERT INTO t2 VALUES (2);
+CREATE TABLE t3 ( c INT );
+INSERT INTO t3 VALUES (2);
+
+SELECT MIN(a) FROM t1, t2 WHERE b IN (SELECT c FROM t3 GROUP BY c);
+
+DROP TABLE t1,t2,t3;
 
 --echo # This must be at the end:
 set optimizer_switch=@subselect_sj_mat_tmp;

sql/opt_sum.cc

@@ -299,7 +299,8 @@ int opt_sum_query(THD *thd,
       is_exact_count= FALSE;
       count= 1;                                 // ensure count != 0
     }
-    else if (tl->is_materialized_derived())
+    else if (tl->is_materialized_derived() || 
+             tl->jtbm_subselect)
     {
       /*
         Can't remove a derived table as it's number of rows is just an