select * from a as a where a.id in (1,2,3,...,100)效率如何
select * from a as a where a.id in (1,2,3,...,100)效率如何
in里面的东西是没有规律的
是从另一个表按条件select出来的
是单这么写效率好,还是select * from a as a inner join b as b on b.xx=xx and a.xx=b.xx效率好
------解决方案--------------------少了好多解析的时间
------解决方案--------------------
------解决方案--------------------
------解决方案--------------------那还是用join吧