MySQL 一个查询语句

Question

A表有字段 a_id
B表有字段 b_id, a_id, mun

查找 mun 总和大于 10 的A表

B表包含多个A表

Answer 1

你的表达能力有问题。
select a_id from A where a_id in( select a_id from B groupby a_id where sum(num)>10)

Answer 2

SELECT * FROM A a,B b WHERE mun>10 AND b.a_id=a.a_id

Answer 3

    select a_id
    from A a
    left join B b on a.a_id = b.a_id 
    group by a.a_id having count(b.num)>10