mysql count 怎么提交效率
有一个程序,先从user表查一定数量的用户$data，再foreach数组，从user表里count(*) where pid=$value['id'] 来统计子集数量
循环200条数据需要5秒多，要是数据多估计就卡死了，该怎么优化？
回复内容：
有一个程序,先从user表查一定数量的用户$data，再foreach数组，从user表里count(*) where pid=$value['id'] 来统计子集数量
循环200条数据需要5秒多，要是数据多估计就卡死了，该怎么优化？
连接查询count(*)使用group by
用Count(1)而不是count(*)可以有一定改善
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