MySQL查询今天、昨天、上周、近30天、去年等的数据的方法
摘要:一、MySQL查询今天、昨天、上周、近30天、去年等的数据的方法: 删除建立时间超过3天的订单记录 delete 订单表 where datediff( dd, order_addtime, getdate() ) > 3 用函数datediff() datediff( dd, 时间1, 时间2 )
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删除重复数据
摘要:delete from 表 where id in (select id from (select max(id) as id,count(列) as count from 表group by 列 having count >1 order by count desc) as tab )
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mysql 数据表中查找重复记录(条数)
摘要:SELECT 字段,COUNT(*) AS COUNT FROM 表名 GROUP BY 字段 HAVING COUNT>1;
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