mysql数据库分表后怎么查询总数据

select s.num1,t.num2 from

(select count(*) num1 from student) s,

(select count(*) num2 from teacher) t

分别用两个子查询查出两个标的记录，即临时表，然后列出来就可以。有问题再留言

select a.name, max(b.log_time) from 表1 as a, 表2 as b where a.id = b.user_id group by a.name 根据您最新的需求，SQL修改如下，保证查询效率没的说： select a.id, a.name, max(b.log_time), ( select c.content from 表2 as c where c.us..

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