MDEV-4863 COALESCE(time_or_datetime) returns wrong results in numeric context

1 files changed, 4 insertions, 6 deletions

diff --git a/sql/item_timefunc.h b/sql/item_timefunc.h
index b17e1c794ee..b0245e6f743 100644
--- a/sql/item_timefunc.h
+++ b/sql/item_timefunc.h
@@ -372,9 +372,11 @@ public:
     max_length=17 + (decimals ? decimals + 1 : 0);
     set_persist_maybe_null(1);
   }
-  void find_num_type() { hybrid_type= decimals ? DECIMAL_RESULT : INT_RESULT; }
+  void find_num_type()
+  { cached_result_type= decimals ? DECIMAL_RESULT : INT_RESULT; }
   double real_op() { DBUG_ASSERT(0); return 0; }
   String *str_op(String *str) { DBUG_ASSERT(0); return 0; }
+  bool date_op(MYSQL_TIME *ltime, uint fuzzydate) { DBUG_ASSERT(0); return true; }
 };
 
 
@@ -451,12 +453,8 @@ public:
   { return save_date_in_field(field); }
   void fix_length_and_dec()
   { 
-    static const uint max_time_type_width[5]=
-    { MAX_DATETIME_WIDTH, MAX_DATETIME_WIDTH, MAX_DATE_WIDTH,
-      MAX_DATETIME_WIDTH, MIN_TIME_WIDTH };
-
     set_persist_maybe_null(1);
-    max_length= max_time_type_width[mysql_type_to_time_type(field_type())+2];
+    max_length= mysql_temporal_int_part_length(field_type());
     if (decimals)
     {
       if (decimals == NOT_FIXED_DEC)