Bug#47371 reference by same column name

At the end of execution top level join execution
we cleanup this join with true argument.
It leads to underlying join cleanup(subquery) with true argument too
and to tmp_table_param->field array cleanup which is required later.
The problem is that Item_func_set_user_var does not set
result_filed which leads to unnecessary repeated excution of subquery
on final stage.
The fix is to set result_field for Item_func_set_user_var.


mysql-test/r/count_distinct.result:
  test result
mysql-test/r/user_var.result:
  test result
mysql-test/t/count_distinct.test:
  test case
mysql-test/t/user_var.test:
  test case
sql/item_func.cc:
  At the end of execution top level join execution
  we cleanup this join with true argument.
  It leads to underlying join cleanup(subquery) with true argument too
  and to tmp_table_param->field array cleanup which is required later.
  The problem is that Item_func_set_user_var does not set
  result_filed which leads to unnecessary repeated excution of subquery
  on final stage.
  The fix is to set result_field for Item_func_set_user_var.

1 files changed, 20 insertions, 0 deletions

diff --git a/mysql-test/r/count_distinct.result b/mysql-test/r/count_distinct.result
index a21748359b9..804bc1f4788 100644
--- a/mysql-test/r/count_distinct.result
+++ b/mysql-test/r/count_distinct.result
@@ -40,6 +40,26 @@ select t2.isbn,city,t1.libname,count(distinct t1.libname) as a from t3 left join
 isbn	city	libname	a
 007	Berkeley	Berkeley Public1	2
 000	New York	New York Public Libra	2
+select t2.isbn,city,@bar:=t1.libname,count(distinct t1.libname) as a
+from t3 left join t1 on t3.libname=t1.libname left join t2
+on t3.isbn=t2.isbn group by city having count(distinct
+t1.libname) > 1;
+isbn	city	@bar:=t1.libname	a
+007	Berkeley	Berkeley Public1	2
+000	New York	New York Public Libra	2
+SELECT @bar;
+@bar
+Berkeley Public2
+select t2.isbn,city,concat(@bar:=t1.libname),count(distinct t1.libname) as a
+from t3 left join t1 on t3.libname=t1.libname left join t2
+on t3.isbn=t2.isbn group by city having count(distinct
+t1.libname) > 1;
+isbn	city	concat(@bar:=t1.libname)	a
+007	Berkeley	Berkeley Public1	2
+000	New York	New York Public Libra	2
+SELECT @bar;
+@bar
+Berkeley Public2
 drop table t1, t2, t3;
 create table t1 (f1 int);
 insert into t1 values (1);