Question

我有一对多关系表。

我希望得到多个id之间共享的最低的other_id。

id other_id
5  5
5  6
5  7
6  6
6  7
7  7

我可以通过动态构建一个SQL语句来实现这一点，并为我想要查询的每个附加id添加一些部分。例如：

select * from (
    select other_id from SomeTable where id = 5
) as a
inner join (
    select other_id from SomeTable where id = 6
) as b
inner join (
    select other_id from SomeTable where id = 7
) as c
on a.other_id = b.other_id
and a.other_id = c.other_id

有更好的方法吗？更具体地说，有没有办法做到这一点，不需要可变数量的连接？我觉得这个问题可能已经有了一个名字和更好的解决方案。

我的查询给了我7号，这就是我想要的。

Answer 1

我目前没有测试它的mysql服务器，但尝试“分组依据”声明：

select 
    other_id 
from 
    SomeTable 
group by 
    other_id having count(*) > 1 
order by 
    other_id asc 
    limit 1

Answer 2

使用MIN进行简单查询

 SELECT MIN(other_id) FROM table

Answer 3

所有ID之间共享的最低other_id

select other_id
from SomeTable
group by other_id
having count(distinct id) = 3
order by other_id limit 1

或动态

select other_id
from SomeTable
group by other_id
having count(distinct id) = (select count(distinct id) from SomeTable) 
order by other_id limit 1

或者如果您想查找特定ID之间共享的最低other_id

select other_id
from SomeTable
where id in (5,6,7)
group by other_id
having count(distinct id) = 3
order by other_id limit 1

Answer 4

虽然，似乎有工作解决方案我想添加我的版本，只是为了展示，我有多聪明; - ）

SELECT other_id FROM SomeTable a INNER JOIN SomeTable b on a.other_id=b.other_id ORDER by other_id ASC LIMIT 1

在一对多关系表中获取最低共享值

4 个答案: