Fixed bug#16861: User defined variable can have a wrong value if a tmp table was

used.

The Item::save_in_field() function is called from fill_record() to fill the 
new row with data while execution of the CREATE TABLE ... SELECT statement.
Item::save_in_field() calls val_xxx() methods in order to get values.
val_xxx() methods do not take into account the result field. Due to this
Item_func_set_user_var::val_xxx() methods returns values from the original
table, not from the temporary one.

The save_in_field() member function is added to the Item_func_set_user_var
class. It detects whether the result field should be used and properly updates
the value of the user variable.

1 files changed, 8 insertions, 1 deletions

diff --git a/mysql-test/r/user_var.result b/mysql-test/r/user_var.result
index 90954fc1ede..753c982155c 100644
--- a/mysql-test/r/user_var.result
+++ b/mysql-test/r/user_var.result
@@ -301,7 +301,14 @@ select @var:=f2 from t1 group by f1 order by f2 desc limit 1;
 select @var;
 @var
 3
-drop table t1;
+create table t2 as select @var:=f2 from t1 group by f1 order by f2 desc limit 1;
+select * from t2;
+@var:=f2
+3
+select @var;
+@var
+3
+drop table t1,t2;
 insert into city 'blah';
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''blah'' at line 1
 SHOW COUNT(*) WARNINGS;