Manual merge of fixes for bugs #7899 "CREATE TABLE .. SELECT .. and

CONVERT_TZ() function does not work well together" and bug #7705 
"CONVERT_TZ() crashes with subquery/WHERE on index column" in 5.0
tree.


mysql-test/r/timezone2.result:
  Auto merged
mysql-test/t/timezone2.test:
  Auto merged
sql/item_timefunc.cc:
  Auto merged
sql/item_timefunc.h:
  Auto merged
sql/set_var.h:
  Auto merged
sql/set_var.cc:
  Manual merge.
sql/sql_lex.cc:
  Ignoring changes in st_lex::unlink_first_table()/link_first_table_back()
  made in 4.1 since they are not applicable to 5.0.
sql/tztime.cc:
  Manual merge.

1 files changed, 6 insertions, 2 deletions

diff --git a/sql/item_timefunc.h b/sql/item_timefunc.h
index dccba7f52b1..917018463e5 100644
--- a/sql/item_timefunc.h
+++ b/sql/item_timefunc.h
@@ -545,12 +545,15 @@ class Item_func_convert_tz :public Item_date_func
   TABLE_LIST *tz_tables;
   /*
     If time zone parameters are constants we are caching objects that
-    represent them.
+    represent them (we use separate from_tz_cached/to_tz_cached members
+    to indicate this fact, since NULL is legal value for from_tz/to_tz
+    members.
   */
+  bool from_tz_cached, to_tz_cached;
   Time_zone *from_tz, *to_tz;
  public:
   Item_func_convert_tz(Item *a, Item *b, Item *c):
-    Item_date_func(a, b, c) {}
+    Item_date_func(a, b, c), from_tz_cached(0), to_tz_cached(0) {}
   longlong val_int();
   double val_real() { return (double) val_int(); }
   String *val_str(String *str);
@@ -558,6 +561,7 @@ class Item_func_convert_tz :public Item_date_func
   bool fix_fields(THD *, struct st_table_list *, Item **);
   void fix_length_and_dec();
   bool get_date(TIME *res, uint fuzzy_date);
+  void cleanup();
 };