显示所有重复数据分组

SELECT 
    origin_id
FROM 
    topk88_product
GROUP BY origin_id 
HAVING count(*)>1

删除所有重复

DELETE FROM topk88_product
WHERE origin_id IN (
    SELECT 
        origin_id
    FROM 
        topk88_product
    GROUP BY origin_id 
    HAVING count(*)>1
);

提示：You can't specify target table 'topk88_product' for update in FROM clause；MySQL 不允许查询一个表的时候，又更新同一个表。解决办法是把要更新的几列数据查询出来做为一个临时表，然后筛选更新。

DELETE FROM topk88_product
WHERE origin_id IN (
    SELECT origin_id FROM(
        SELECT origin_id FROM topk88_product GROUP BY origin_id HAVING count(*)>1
    ) t
)

上面操作会把所有重复数据全部删除，可以设置只保留ID最小的那一条数据。

DELETE FROM topk88_product
WHERE origin_id IN (
  SELECT origin_id FROM(
    SELECT origin_id FROM topk88_product GROUP BY origin_id HAVING count(*)>1
  ) t
) 
AND id NOT IN (
  SELECT t2.min_id FROM(
    SELECT min(id) AS min_id FROM topk88_product GROUP BY origin_id HAVING count(*)>1
  ) t2
);

上面是正确的MySQL语句。

修改时间 2021-03-17