MWL#17: Table elimination:

- Fix a trivial problem when OR-merging two multi-equalities
- Amend testsuite to provide full gcov coverage

mysql-test/r/table_elim.result:
  MWL#17: Table elimination:
  - Amend testsuite to provide full gcov coverage
mysql-test/t/table_elim.test:
  MWL#17: Table elimination:
  - Amend testsuite to provide full gcov coverage

1 files changed, 58 insertions, 0 deletions

diff --git a/mysql-test/t/table_elim.test b/mysql-test/t/table_elim.test
index cab90cb5286..642c5d51d62 100644
--- a/mysql-test/t/table_elim.test
+++ b/mysql-test/t/table_elim.test
@@ -278,3 +278,61 @@ explain select t1.a from t1 left join t3 on t3.pk1=t1.a and t3.pk2 IS NULL;
 
 drop table t1,t2,t3;
 
+--echo #
+--echo # Multi-equality tests 
+--echo #
+create table t1 (a int, b int, c int, d int);
+insert into t1 values (0,0,0,0),(1,1,1,1),(2,2,2,2),(3,3,3,3);
+
+create table t2 (pk int primary key, b int, c int);
+insert into t2 select a,a,a from t1 where a in (1,2);
+
+explain 
+select t1.* 
+from t1 left join t2 on t2.pk=t2.c and t2.b=t1.a and t1.a=t1.b and t2.c=t2.b
+where t1.d=1;
+
+explain 
+select t1.* 
+from 
+    t1 
+  left join 
+    t2 
+  on (t2.pk=t2.c and t2.b=t1.a and t1.a=t1.b and t2.c=t2.b) or
+     (t2.pk=t2.c and t2.b=t1.a and t1.a=t1.b and t2.c=t2.b) 
+where t1.d=1;
+
+--echo #This can't be eliminated:
+explain 
+select t1.* 
+from 
+    t1 
+  left join 
+    t2 
+  on (t2.pk=t2.c and t2.b=t1.a and               t2.c=t1.b) or
+     (t2.pk=t2.c and               t1.a=t1.b and t2.c=t1.b) 
+where t1.d=1;
+
+explain 
+select t1.* 
+from 
+    t1 
+  left join 
+    t2 
+  on (t2.pk=t2.c and t2.b=t1.a and t2.c=t1.b) or
+     (t2.pk=t2.c and               t2.c=t1.b) 
+;
+
+explain 
+select t1.* 
+from t1 left join t2 on t2.pk=3 or t2.pk= 4;
+
+explain 
+select t1.* 
+from t1 left join t2 on t2.pk=3 or t2.pk= 3;
+
+explain 
+select t1.* 
+from t1 left join t2 on (t2.pk=3 and t2.b=3) or (t2.pk= 4 and t2.b=3);
+
+drop table t1, t2;