MDEV-26345 Skip "auxiliary" fields in spider group by handler

sql/sql_select.h

@@ -1473,7 +1473,7 @@ class JOIN :public Sql_alloc
 
     Then, ORDER/GROUP BY and Window Function code add columns that need to
     be saved to be available in the post-group-by context. These extra columns
-    are added to the front, because this->all_fields points to the suffix of
+    are added to the front, because this->fields_list points to the suffix of
     this list.
   */
   List<Item> all_fields;

storage/spider/mysql-test/spider/r/direct_join.result

@@ -76,7 +76,7 @@ a	b	c
 connection child2_1;
 SELECT argument FROM mysql.general_log WHERE argument LIKE '%select %';
 argument
-select t0.`b` `b`,t0.`a` `a`,t2.`b` `b`,t2.`c` `c` from `auto_test_remote`.`ta_r` t0 join `auto_test_remote`.`ta_r_3` t1 join `auto_test_remote`.`ta_r_int` t2 where ((t0.`a` = t1.`a`) and (t2.`a` = t1.`a`)) order by t0.`b` desc limit 1,2
+select 1,t0.`a` `a`,t2.`b` `b`,t2.`c` `c` from `auto_test_remote`.`ta_r` t0 join `auto_test_remote`.`ta_r_3` t1 join `auto_test_remote`.`ta_r_int` t2 where ((t0.`a` = t1.`a`) and (t2.`a` = t1.`a`)) order by t0.`b` desc limit 1,2
 SELECT argument FROM mysql.general_log WHERE argument LIKE '%select %'
 SELECT a, b, date_format(c, '%Y-%m-%d %H:%i:%s') FROM ta_r ORDER BY a;
 a	b	date_format(c, '%Y-%m-%d %H:%i:%s')

storage/spider/mysql-test/spider/r/direct_join_using.result

@@ -79,7 +79,7 @@ a	b	c
 connection child2_1;
 SELECT argument FROM mysql.general_log WHERE argument LIKE '%select %';
 argument
-select t0.`b` `b`,t0.`a` `a`,t2.`b` `b`,t2.`c` `c` from `auto_test_remote`.`ta_r` t0 join `auto_test_remote`.`ta_r_3` t1 join `auto_test_remote`.`ta_r_int` t2 where ((t0.`a` = t1.`a`) and (t2.`a` = t1.`a`)) order by t0.`b` desc
+select 1,t0.`a` `a`,t2.`b` `b`,t2.`c` `c` from `auto_test_remote`.`ta_r` t0 join `auto_test_remote`.`ta_r_3` t1 join `auto_test_remote`.`ta_r_int` t2 where ((t0.`a` = t1.`a`) and (t2.`a` = t1.`a`)) order by t0.`b` desc
 SELECT argument FROM mysql.general_log WHERE argument LIKE '%select %'
 SELECT a, b, date_format(c, '%Y-%m-%d %H:%i:%s') FROM ta_r ORDER BY a;
 a	b	date_format(c, '%Y-%m-%d %H:%i:%s')

storage/spider/mysql-test/spider/r/direct_left_join.result

@@ -79,7 +79,7 @@ a	b	c
 connection child2_1;
 SELECT argument FROM mysql.general_log WHERE argument LIKE '%select %';
 argument
-select t0.`b` `b`,t0.`a` `a`,t2.`b` `b`,t2.`c` `c` from `auto_test_remote`.`ta_r` t0 left join `auto_test_remote`.`ta_r_3` t1 on (t1.`a` = t0.`a`) left join `auto_test_remote`.`ta_r_int` t2 on (t2.`a` = t0.`a`) where 1 order by t0.`b` desc
+select 1,t0.`a` `a`,t2.`b` `b`,t2.`c` `c` from `auto_test_remote`.`ta_r` t0 left join `auto_test_remote`.`ta_r_3` t1 on (t1.`a` = t0.`a`) left join `auto_test_remote`.`ta_r_int` t2 on (t2.`a` = t0.`a`) where 1 order by t0.`b` desc
 SELECT argument FROM mysql.general_log WHERE argument LIKE '%select %'
 SELECT a, b, date_format(c, '%Y-%m-%d %H:%i:%s') FROM ta_r ORDER BY a;
 a	b	date_format(c, '%Y-%m-%d %H:%i:%s')

storage/spider/mysql-test/spider/r/direct_right_join.result

@@ -79,7 +79,7 @@ a	b	c
 connection child2_1;
 SELECT argument FROM mysql.general_log WHERE argument LIKE '%select %';
 argument
-select t0.`b` `b`,t0.`a` `a`,t2.`b` `b`,t2.`c` `c` from `auto_test_remote`.`ta_r_int` t2 left join (`auto_test_remote`.`ta_r_3` t1 join `auto_test_remote`.`ta_r` t0) on ((t0.`a` = t2.`a`) and (t1.`a` = t2.`a`)) where 1 order by t0.`b` desc
+select 1,t0.`a` `a`,t2.`b` `b`,t2.`c` `c` from `auto_test_remote`.`ta_r_int` t2 left join (`auto_test_remote`.`ta_r_3` t1 join `auto_test_remote`.`ta_r` t0) on ((t0.`a` = t2.`a`) and (t1.`a` = t2.`a`)) where 1 order by t0.`b` desc
 SELECT argument FROM mysql.general_log WHERE argument LIKE '%select %'
 SELECT a, b, date_format(c, '%Y-%m-%d %H:%i:%s') FROM ta_r ORDER BY a;
 a	b	date_format(c, '%Y-%m-%d %H:%i:%s')

storage/spider/spd_db_mysql.cc

@@ -13971,6 +13971,7 @@ int spider_mbase_handler::append_list_item_select(
   Item *item;
   Field *field;
   const char *item_name;
+  uint skip= select->elements - fields->get_first_table_holder()->table->pos_in_table_list->select_lex->join->fields_list.elements;
   DBUG_ENTER("spider_mbase_handler::append_list_item_select");
   DBUG_PRINT("info",("spider this=%p", this));
   begin = str->length();
@@ -13981,6 +13982,15 @@ int spider_mbase_handler::append_list_item_select(
       DBUG_PRINT("info",("spider const item"));
       continue;
     }
+    if (skip > 0)
+    {
+      str->reserve(2);
+      str->q_append("1", 1);
+      field = *(fields->get_next_field_ptr());
+      str->q_append(SPIDER_SQL_COMMA_STR, SPIDER_SQL_COMMA_LEN);
+      skip--;
+      continue;
+    }
     if ((error_num = spider_db_print_item_type(item, NULL, spider, str,
       alias, alias_length, dbton_id, use_fields, fields)))
     {