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+#
+# Tests for non-merged semi-joins
+#
+--disable_warnings
+drop table if exists t0, t1, t2, t3, t4;
+--enable_warnings
+
+set @save_optimizer_switch=@@optimizer_switch;
+
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+
+
+# Check the case of subquery having agggregates but not having grouping
+
+create table t1 as select * from t0;
+--echo # The following should use full scan on <subquery2> and it must scan 1 row:
+explain select * from t0 where a in (select max(a) from t1);
+select * from t0 where a in (select max(a) from t1);
+
+# Ok, now check the trivial match/no-match/NULL on the left/NULL on the right cases
+insert into t1 values (11);
+select * from t0 where a in (select max(a) from t1);
+delete from t1 where a=11;
+
+insert into t0 values (NULL);
+select * from t0 where a in (select max(a) from t1);
+delete from t0 where a is NULL;
+
+delete from t1;
+select * from t0 where a in (select max(a) from t1);
+
+insert into t0 values (NULL);
+select * from t0 where a in (select max(a) from t1);
+delete from t0 where a is NULL;
+
+drop table t1;
+
+#
+# Try with join subqueries
+#
+
+create table t1 (a int, b int);
+insert into t1 select a,a from t0; # 10 rows
+create table t2 as select * from t1 where a<5; # 5 rows
+create table t3 as select (A.a + 10*B.a) as a from t0 A, t0 B; # 100 rows
+alter table t3 add primary key(a);
+
+--echo # The following should have do a full scan on <subquery2> and scan 5 rows
+--echo # (despite that subquery's join output estimate is 50 rows)
+explain select * from t3 where a in (select max(t2.a) from t1, t2 group by t2.b);
+
+--echo # Compare to this which really will have 50 record combinations:
+explain select * from t3 where a in (select max(t2.a) from t1, t2 group by t2.b, t1.b);
+
+--echo # Outer joins also work:
+explain select * from t3
+where a in (select max(t2.a) from t1 left join t2 on t1.a=t2.a group by t2.b, t1.b);
+
+#
+# Check if joins on the outer side also work
+#
+create table t4 (a int, b int, filler char(20), unique key(a,b));
+insert into t4 select A.a + 10*B.a, A.a + 10*B.a, 'filler' from t0 A, t0 B; # 100 rows
+explain select * from t0, t4 where
+ t4.b=t0.a and t4.a in (select max(t2.a) from t1, t2 group by t2.b);
+
+insert into t4 select 100 + (B.a *100 + A.a), 100 + (B.a*100 + A.a), 'filler' from t4 A, t0 B;
+explain select * from t4 where
+ t4.a in (select max(t2.a) from t1, t2 group by t2.b) and
+ t4.b in (select max(t2.a) from t1, t2 group by t2.b);
+
+drop table t1,t2,t3,t4;
+
+drop table t0;
+