MDEV-9972 Least function retuns date in date time format

mysql-test/r/type_date.result

@@ -442,6 +442,7 @@ select 1 from t1 as t1_0 inner join t1 as t2 on (t1_0.a <=> now()) join t1 on 1;
 drop table t1;
 #
 # MDEV-9521 Least function returns 0000-00-00 for null date columns instead of null
+# MDEV-9972 Least function retuns date in date time format
 #
 CREATE TABLE t1 (
 id BIGINT NOT NULL,
@@ -465,9 +466,9 @@ LEAST(IFNULL(t2.date_fin, IFNULL(t1.date_fin, NULL)),
 IFNULL(t1.date_fin, IFNULL(t2.date_fin, NULL))) AS date_fin
 FROM t1 LEFT JOIN t2 ON (t1.id=t2.id);
 id	date_debut	date_fin
-1	2016-01-01	2016-01-31 00:00:00
-2	2016-02-01	2016-01-28 00:00:00
-3	2016-03-01	2016-03-31 00:00:00
+1	2016-01-01	2016-01-31
+2	2016-02-01	2016-01-28
+3	2016-03-01	2016-03-31
 4	2016-04-01	NULL
 DROP TABLE t1,t2;
 SELECT

mysql-test/t/type_date.test

@@ -388,6 +388,7 @@ drop table t1;
 
 --echo #
 --echo # MDEV-9521 Least function returns 0000-00-00 for null date columns instead of null
+--echo # MDEV-9972 Least function retuns date in date time format
 --echo #
 CREATE TABLE t1 (
   id BIGINT NOT NULL,

sql/item_func.cc

@@ -2939,12 +2939,13 @@ bool Item_func_min_max::get_date(MYSQL_TIME *ltime, ulonglong fuzzy_date)
   }
   unpack_time(min_max, ltime);
 
-  if (compare_as_dates->field_type() == MYSQL_TYPE_DATE)
+  enum_field_types ftype= compare_as_dates->field_type();
+  if (ftype == MYSQL_TYPE_DATE || ftype == MYSQL_TYPE_NEWDATE)
   {
     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)
+  else if (ftype == MYSQL_TYPE_TIME)
   {
     ltime->time_type= MYSQL_TIMESTAMP_TIME;
     ltime->hour+= (ltime->month * 32 + ltime->day) * 24;