mysql - 需要帮助从重复数据中查询最大值，按多列分组

Question

我有很多重复的数据，我试图只更新数量最多的行，按多列分组。我试过了，但没用。任何帮助，将不胜感激。谢谢

UPDATE `polls` AS `p1`
INNER JOIN (
   SELECT *
   FROM `polls`
   GROUP BY `server_id`, `product_id`, `poll_date`
   ORDER BY max(quantity)
   HAVING COUNT(*) > 1
) AS `p2`
   ON `p2`.`server_id` = `p1`.`server_id`
   AND `p2`.`product_id` = `p1`.`product_id`
   AND `p2`.`poll_date` = `p1`.`poll_date`
   SET `p1`.`updated_by` = 'admin';

Answer 1

试试这个

 ....
 INNER JOIN (
   SELECT * , max(quantity)
   FROM `polls`
   GROUP BY `server_id`, `product_id`
   ORDER BY max(quantity) desc 
 )
 ....