Fix for bug#42009: SELECT into variable gives different results to direct SELECT

Problem: storing "SELECT ... INTO @var ..." results in variables we used val_xxx()
methods which returned results of the current row. 
So, in some cases (e.g. SELECT DISTINCT, GROUP BY or HAVING) we got data
from the first row of a new group (where we evaluate a clause) instead of
data from the last row of the previous group.

Fix: use val_xxx_result() counterparts to get proper results.


mysql-test/r/distinct.result:
  Fix for bug#42009: SELECT into variable gives different results to direct SELECT
    - results adjusted.
mysql-test/r/user_var.result:
  Fix for bug#42009: SELECT into variable gives different results to direct SELECT
    - test result.
mysql-test/t/user_var.test:
  Fix for bug#42009: SELECT into variable gives different results to direct SELECT
    - test case.
sql/item_func.cc:
  Fix for bug#42009: SELECT into variable gives different results to direct SELECT
    - Item_func_set_user_var::save_item_result() added to evaluate and store 
      an item's result into a user variable.
sql/item_func.h:
  Fix for bug#42009: SELECT into variable gives different results to direct SELECT
    - Item_func_set_user_var::save_item_result() added to evaluate and store 
      an item's result into a user variable.
sql/sql_class.cc:
  Fix for bug#42009: SELECT into variable gives different results to direct SELECT
    - use Item_func_set_user_var::save_item_result() to store results into user 
      variables.

1 files changed, 1 insertions, 0 deletions

diff --git a/sql/item_func.h b/sql/item_func.h
index 7e15a536cf2..33aeddfe6e6 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -1308,6 +1308,7 @@ public:
   bool send(Protocol *protocol, String *str_arg);
   void make_field(Send_field *tmp_field);
   bool check(bool use_result_field);
+  void save_item_result(Item *item);
   bool update();
   enum Item_result result_type () const { return cached_result_type; }
   bool fix_fields(THD *thd, Item **ref);