如何将这两个查询结合起来，使结果在一个表中？

Question

第一个查询：

SELECT integration_department_map.foreign_department_key AS 'Department Code', department.department_name AS 'Department Name'
FROM integration_department_map
JOIN department ON department.department_id = integration_department_map.department_id
WHERE integration_department_map.client_id = '10134';

第二个查询：

SELECT integration_department_map.foreign_department_key AS 'Department Code', location.location_name AS 'Location Name'
FROM integration_department_map
JOIN location ON location.location_id = integration_department_map.location_id
WHERE integration_department_map.client_id = '10134';

它们都分别返回所需的结果，但我想知道是否有一种方法可以将它们写为一个查询？

Answer 1

正如蜜獾在评论中所建议的那样。 只需向位置表添加一个join ，例如：

SELECT 
    i.foreign_department_key AS `Department Code`, 
    d.department_name AS `Department Name`, 
    l.location_name AS `Location Name`
FROM integration_department_map i
JOIN department d
ON d.department_id = i.department_id
JOIN location l
ON l.location_id = i.location_id
WHERE i.client_id = 10134

如果它应该是一个int ，则删除id周围的引号。

Answer 2

也许您正在寻找的是 LEFT JOIN 而不是 JOIN（内连接）。 原始 integration_department_map 中有多少行满足 WHERE 子句，它们是同一行吗？

也许这会奏效-

SELECT 
    i.id,
    i.foreign_department_key AS `Department Code`, 
    d.department_name AS `Department Name`, 
    l.location_name AS `Location Name`
FROM integration_department_map i
LEFT JOIN department d ON d.department_id = i.department_id
LEFT JOIN location l   ON l.location_id = i.location_id
WHERE i.client_id = 10134