在mysql查询中计算两个不同的行答案

【问题标题】：Count two different rows in mysql query在mysql查询中计算两个不同的行
【发布时间】：2017-01-19 17:52:26
【问题描述】：

我有组织。每个组织都可以有成员和项目。我想获取具有成员和项目数量的组织列表。例如，

Organization | Members | Projects | Action
------------------------------------------
Org 1        | 5       | 6        | Delete - Edit
Org 2        | 2       | 9        | Delete - Edit

我正在使用这个查询，

SELECT COUNT(m.id) as members, COUNT(p.id) as projects, 
       o.status,o.organization_name,o.logo, o.id as id
from tbl_organizations o 
LEFT JOIN tbl_organization_members m  ON (o.id = m.organization_id) 
LEFT JOIN tbl_projects p ON (o.id = p.organization_id) 
WHERE o.status= 'active' AND o.created_by= 1

但是项目数量的产出等于成员的数量。如何使用查询制作上述示例？

【问题讨论】：

标签： mysql

【解决方案1】：

按组织列分组并计算不同的 ID

SELECT o.status,o.organization_name, o.logo, o.id as id,
       COUNT(distinct m.id) as members, COUNT(distinct p.id) as projects, 
from tbl_organizations o 
LEFT JOIN tbl_organization_members m  ON (o.id = m.organization_id) 
LEFT JOIN tbl_projects p ON (o.id = p.organization_id) 
WHERE o.status= 'active' 
AND o.created_by= 1
GROUP BY o.status, o.organization_name, o.logo, o.id

【讨论】：

【解决方案2】：

试试这个方法：

SELECT o.id as id, o.organization_name, cnt_ as members, cnt_p as projects
from tbl_organizations o 
LEFT JOIN (
   SELECT organization_id, COUNT(id) cnt_m
   FROM tbl_organization_members
   GROUP BY organization_id
) m  ON (o.id = m.organization_id) 
LEFT JOIN (
   SELECT organization_id, COUNT(id) cnt_p
   FROM tbl_projects 
   GROUP BY organization_id
) p ON (o.id = p.organization_id) 
WHERE o.status= 'active' AND o.created_by= 1

这样你JOIN 到一个已经聚合 版本的成员/项目表，以便获得每个organization_id 的成员/项目计数。

【讨论】：

【解决方案3】：

您可以关联子查询：

SELECT
    o.id as Organization,
    (SELECT COUNT(*) FROM tbl_organization_members WHERE organization_id = o.id) as members,
    (SELECT COUNT(*) FROM tbl_projects WHERE organization_id = o.id) as projects
FROM
    tbl_organizations o
WHERE
    o.status= 'active' AND o.created_by = 1

【讨论】：