mysql - 在报告模块中获取分配项目超过 2 个的联系人

Question

如何获取拥有 2 个产品的联系人数据？

联系人表

id   name
1    Jon Doe

项目表

id  Project_name
1   prod_a
2   prod_b

project_contacts 表

id    contact_id   project_id
1     1            1
2     1            2

我想要那些同时拥有 prod_a 和 prod_b 的联系人的结果

如何在报表模块中查询这个

select c.name 
from
Contacts c,
Projects p,
project_contacts pc
WHERE
c.id = pc.contact_id
and p.id = pc.project_id
and p.name = "prod_a"
and p.name = "prod_b"

我要获取结果

name   
--------
John Doe
John Doe

Answer 1

您需要在表之间执行JOIN，然后像group by

select c.name 
from Contacts c
join project_contacts pc on c.id = pc.contact_id
join Projects p on o.id = pc.project_id
WHERE p.Project_name in ('prod_a','prod_b')
group by c.id
having count(distinct c.name) = 2;