Mysql Group By、limit、where

1.Mysql执行顺序

写的顺序：select … from… where…. group by… having… order by..执行顺序：from… where…group by… having…. select … order by…

按name分组查最新一条操作记录select * from (select * from a order by time desc) as b group by b.name指定字段获取最大值 SELECT id, max(operat_time) FROM tb GROUP BY id;# 推荐使用select cluesTaracking_id,cluesId,MAX(trackingTime),fail_why from cluestrackinggroup by cluesIdorder by trackingTime desc

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分组后统计其他字段(也需去重)

selectdate_format(create_time, '%Y-%m-%d') date_,count(distinct user_id) countsfromawheredel_ = 1group bydate_order bydate_ desc

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