MDEV-9707 MAX(timestamp(6) column) in correlated sub-query returns...

MDEV-9707 MAX(timestamp(6) column) in correlated sub-query returns non-existent row data in original table

special treatment for  temporal values in
create_tmp_field_from_item().

old code only did it when result_type() was STRING_RESULT,
but Item_cache_temporal::result_type() is INT_RESULT

mysql-test/r/cache_temporal_4265.result

@@ -7,4 +7,17 @@ a
 2002-03-04
 Warnings:
 Note	1003	2000-01-01
+set debug_dbug='';
+drop table t1;
+create table t1 (id int not null, ut timestamp(6) not null);
+insert into t1 values(1, '2001-01-01 00:00:00.2');
+insert into t1 values(1, '2001-01-01 00:00:00.1');
+select * from t1;
+id	ut
+1	2001-01-01 00:00:00.200000
+1	2001-01-01 00:00:00.100000
+select (select max(m2.ut) from t1 m2 where m1.id <> 0) from t1 m1;
+(select max(m2.ut) from t1 m2 where m1.id <> 0)
+2001-01-01 00:00:00.200000
+2001-01-01 00:00:00.200000
 drop table t1;

mysql-test/t/cache_temporal_4265.test

@@ -7,5 +7,16 @@ create table t1 (a date);
 insert t1 values ('2000-01-02'), ('2001-02-03'), ('2002-03-04');
 set debug_dbug='d,str_to_datetime_warn';
 select * from t1 where a > date_add('2000-01-01', interval 5 day);
+set debug_dbug='';
+drop table t1;
+
+#
+# MDEV-9707 MAX(timestamp(6) column) in correlated sub-query returns non-existent row data in original table
+#
+create table t1 (id int not null, ut timestamp(6) not null);
+insert into t1 values(1, '2001-01-01 00:00:00.2');
+insert into t1 values(1, '2001-01-01 00:00:00.1');
+select * from t1;
+select (select max(m2.ut) from t1 m2 where m1.id <> 0) from t1 m1;
 drop table t1;
 

sql/sql_select.cc

@@ -14544,6 +14544,14 @@ static Field *create_tmp_field_from_item(THD *thd, Item *item, TABLE *table,
   Field *new_field;
   LINT_INIT(new_field);
 
+  /*
+    To preserve type or DATE/TIME and GEOMETRY fields,
+    they need to be handled separately.
+  */
+  if (item->cmp_type() == TIME_RESULT ||
+      item->field_type() == MYSQL_TYPE_GEOMETRY)
+    new_field= item->tmp_table_field_from_field_type(table, 1);
+  else
   switch (item->result_type()) {
   case REAL_RESULT:
     new_field= new Field_double(item->max_length, maybe_null,
@@ -14566,18 +14574,11 @@ static Field *create_tmp_field_from_item(THD *thd, Item *item, TABLE *table,
   case STRING_RESULT:
     DBUG_ASSERT(item->collation.collation);
   
-    /*
-      DATE/TIME and GEOMETRY fields have STRING_RESULT result type. 
-      To preserve type they needed to be handled separately.
-    */
-    if (item->cmp_type() == TIME_RESULT ||
-        item->field_type() == MYSQL_TYPE_GEOMETRY)
-      new_field= item->tmp_table_field_from_field_type(table, 1);
     /* 
       Make sure that the blob fits into a Field_varstring which has 
       2-byte lenght. 
     */
-    else if (item->max_length/item->collation.collation->mbmaxlen > 255 &&
+    if (item->max_length/item->collation.collation->mbmaxlen > 255 &&
              convert_blob_length <= Field_varstring::MAX_SIZE && 
              convert_blob_length)
       new_field= new Field_varstring(convert_blob_length, maybe_null,