Question

我已经使用邻接模型来表示子/父关系。

它被用于镜像公司层次结构，每个员工都有一个经理。员工和经理都存储在同一个表中 - 因此managerID字段指的是特定经理的用户ID。

下面是我的表格结构： userID - email - password - firstName - lastName - officeID - departmentID - managerID - roleID - username

因此，managerID是外键，但源自相同的架构。

我要做的是显示一个表格，其中包含有关系统用户的信息 - 包括他们的经理是谁。

到目前为止，我已使用以下SQL语句的多个连接实现了此目的：

SELECT user.firstName, user.lastName, office.officeName, department.departmentTitle, role.roleName
FROM user, office, department, role
WHERE user.officeID = office.officeID
AND user.departmentID = department.departmentID
AND user.roleID = role.roleID

但是，我不确定如何显示经理的姓名。

任何帮助将不胜感激。

Answer 1

只需使用managerID=m.userID条件

再次加入用户表

m.firstName和m.lastName是经理的姓名

SELECT user.firstName, user.lastName, m.firstName,m.lastName, office.officeName, department.departmentTitle, role.roleName
FROM user as u, user as m, office, department, role
WHERE u.officeID = office.officeID
AND u.departmentID = department.departmentID
AND u.roleID = role.roleID
AND u.managerID=m.userID

Answer 2

如果每个用户都有一个管理员（并且managerID不为空），您可以安全地将LEFT JOIN更改为内部JOIN。

SELECT u.firstName
     , u.lastName
     , office.officeName
     , department.departmentTitle
     , role.roleName
     , manager.firstName AS managerFirstName
     , manager.lastName AS managerLastName
  FROM user AS u
    JOIN office
      ON u.officeID = office.officeID
    JOIN department
      ON u.departmentID = department.departmentID
    JOIN role
      ON u.roleID = role.roleID
    LEFT JOIN user AS manager
      ON u.managerID = manager.userID

Answer 3

您的查询仅提取用户。要获取管理器名称，您需要再次加入用户表，如下所示：

SELECT u.firstName, u.lastName, 
       o.officeName, d.departmentTitle, 
       r.roleName, 
       m.firstName AS mFN, m.lastName AS mLN
FROM user u JOIN office o ON (u.officeID = o.officeID)
            JOIN department d ON (u.departmentID = d.departmentID)
            JOIN role r ON (u.roleID = r.roleID)
            JOIN user m ON (u.manager_id=m.user_id);

Adjacency Model MySQL语法

3 个答案: