MySql去重

了解group by

SELECT MAX(rowid)
FROM people GROUP BY name

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SELECT MAX(id)
FROM table GROUP BY col1,col2,col3

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我本地mysql 不能查询该表的同时 又进行delete or update 操作 ，所以 加粗的部分为重点
DELETE FROM tableName WHERE
id NOT IN(
SELECT id FROM (
SELECT id FROM tableName GROUP BY col1 ,col2
)
AS a
)