removed wrong distinct UNION detection (BUG#6565)

mysql-test/r/derived.result:
  test of union subquery in the FROM clause with complex distinct/all
mysql-test/t/derived.test:
  test of union subquery in the FROM clause with complex distinct/all
sql/sql_derived.cc:
  removed wrong distinct UNION detection

1 files changed, 19 insertions, 0 deletions

diff --git a/mysql-test/r/derived.result b/mysql-test/r/derived.result
index 61d745d0236..b4d9a921178 100644
--- a/mysql-test/r/derived.result
+++ b/mysql-test/r/derived.result
@@ -339,3 +339,22 @@ select distinct sum(b) from (select a,b from t1) y group by a;
 sum(b)
 4
 drop table t1;
+create table t1(a int);
+create table t2(a int);
+create table t3(a int);
+insert into t1 values(1),(1);
+insert into t2 values(2),(2);
+insert into t3 values(3),(3);
+select * from t1 union distinct select * from t2 union all select * from t3;
+a
+1
+2
+3
+3
+select * from (select * from t1 union distinct select * from t2 union all select * from t3) X;
+a
+1
+2
+3
+3
+drop table t1, t2, t3;