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MySQL中删除多余的重复记录

时间:2021-07-01 10:21:17 帮助过:17人阅读

检查重复code1 select count(identity) num, identity from event_log where code=code1 group by identity having count(identity) > 1 order by num desc

删除重复记录

DELETE FROM event_log WHERE `code`=code1 AND identity IN (
    SELECT identity from (
        SELECT identity FROM event_log WHERE code=code1 GROUP BY identity HAVING count(identity) > 1
    ) a
) AND id NOT IN (
    SELECT keepId FROM (
        SELECT min(id) keepId FROM event_log WHERE code=code1 GROUP BY identity HAVING count(identity) > 1
    ) b
)

其中 a 和 b 两个中间表的作用是, 避免执行时出现  You can‘t specify target table ‘xxxxx‘ for update in FROM clause 错误

MySQL中删除多余的重复记录

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