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  • MySQL删除重复数据

    1 GROUP BY 和HAVING组合查询出所有重复记录

    SELECT *  FROM brand WHERE name IN  (SELECT name FROM brand  GROUP BY `name` HAVING COUNT(`name`)>1 );

    2 mysql不支持对同一张表查询的同时进行删除或更改的操作,所以直接将SELECT改为DELETE会报错:

    DELETE * FROM brand WHERE name IN (SELECT name FROM brand GROUP BY `name` HAVING COUNT(`name`)>1 ) AND created_date ="2019-05-22";

    3 查询name的语句设置别为一个临时表,并根据时间删除重复和数据

    DELETE  FROM brand WHERE name IN (SELECT t.name FROM (SELECT name FROM brand  GROUP BY `name` HAVING COUNT(`name`)>1 ) t )AND created_date ="2019-05-22";
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  • 原文地址:https://www.cnblogs.com/pandaly/p/10906068.html
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