Question

mysql怎么根据一个表查询到的值作为条件查询另一个表的值

从成绩表中查询分数前15的score,并根据对应的userid在user表中查询对应的姓名并把姓名和分数输出

Answer 1

假设你成绩表名是user，成绩表名师mark，两表用uid做关联：
select U.uid, U.name,M.score from user as U inner join (select uid, score from Mark order by score desc limit 15) as M on U.uid = M.uid；

Answer 2

select u.name,m.score from
user u
left join mark m on m.userid=u.userid
where mark.score>15