Use default character set for expressions

- Force usage of () around complex DEFAULT expressions
- Give error if DEFAULT expression contains invalid characters
- Don't use const_charset_conversion for stored Item_func_sysconf expressions
  as the result is not constaint over different executions
- Fixed Item_func_user() to not store calculated value in str_value

1 files changed, 2 insertions, 0 deletions

diff --git a/sql/item_timefunc.h b/sql/item_timefunc.h
index ee6394dac37..e0624688f05 100644
--- a/sql/item_timefunc.h
+++ b/sql/item_timefunc.h
@@ -854,6 +854,7 @@ public:
   bool get_date(MYSQL_TIME *res, ulonglong fuzzy_date);
   bool eq(const Item *item, bool binary_cmp) const;
   void print(String *str, enum_query_type query_type);
+  bool need_parentheses_in_default() { return true; }
 };
 
 
@@ -931,6 +932,7 @@ public:
   String *val_str(String *a);
   void fix_length_and_dec();
   void print(String *str, enum_query_type query_type);
+  bool need_parentheses_in_default() { return true; }
 };