MDEV-4652 Wrong result for CONCAT(GREATEST(TIME('00:00:01'),TIME('00:00:00'))

mysql-test/r/type_time.result

@@ -182,5 +182,14 @@ NULL
 Warnings:
 Warning	1292	Incorrect datetime value: '0000-00-00 00:00:00'
 #
+# MDEV-4652 Wrong result for CONCAT(GREATEST(TIME('00:00:01'),TIME('00:00:00')))
+#
+SELECT CONCAT(GREATEST(TIME('00:00:01'),TIME('00:00:00')));
+CONCAT(GREATEST(TIME('00:00:01'),TIME('00:00:00')))
+00:00:01.000000
+SELECT CONCAT(GREATEST(TIME('32 00:00:01'),TIME('00:00:00')));
+CONCAT(GREATEST(TIME('32 00:00:01'),TIME('00:00:00')))
+768:00:01.000000
+#
 # End of 5.3 tests
 #

mysql-test/t/type_time.test

@@ -128,6 +128,12 @@ drop table t1;
 --echo #
 SELECT CONVERT_TZ(GREATEST(TIME('00:00:00'),TIME('00:00:00')),'+00:00','+7:5');
 
+--echo #
+--echo # MDEV-4652 Wrong result for CONCAT(GREATEST(TIME('00:00:01'),TIME('00:00:00')))
+--echo #
+SELECT CONCAT(GREATEST(TIME('00:00:01'),TIME('00:00:00')));
+SELECT CONCAT(GREATEST(TIME('32 00:00:01'),TIME('00:00:00')));
+
 --echo #
 --echo # End of 5.3 tests
 --echo #

sql/item.cc

@@ -252,7 +252,8 @@ String *Item::val_string_from_decimal(String *str)
 String *Item::val_string_from_date(String *str)
 {
   MYSQL_TIME ltime;
-  if (get_date(&ltime, 0) ||
+  if (get_date(&ltime,
+               field_type() == MYSQL_TYPE_TIME ? TIME_TIME_ONLY : 0) ||
       str->alloc(MAX_DATE_STRING_REP_LENGTH))
   {
     null_value= 1;

sql/item_func.cc

@@ -2480,6 +2480,13 @@ bool Item_func_min_max::get_date(MYSQL_TIME *ltime, uint fuzzy_date)
     ltime->time_type= MYSQL_TIMESTAMP_DATE;
     ltime->hour= ltime->minute= ltime->second= ltime->second_part= 0;
   }
+  else if (compare_as_dates->field_type() == MYSQL_TYPE_TIME)
+  {
+    ltime->time_type= MYSQL_TIMESTAMP_TIME;
+    ltime->hour+= (ltime->month * 32 + ltime->day) * 24;
+    ltime->month= ltime->day= 0;
+  }
+
 
   return 0;
 }