sql - SQL，获取外键值。外键引用同一张表

Question

MS SQL 服务器数据库。

我有这个简单的结构：（抱歉主键不在正确的位置）

在 TEACHER 表中，我有一个外键“Chief”，它引用 TEACHER.ID（同一张表）。在进行 SELECT 查询时，如何获取不是整数（Teacher.ID），而是一个酋长的姓名（TEACHER.Name for Chief）？

这个只得到一个整数（酋长的 ID）：

SELECT DEPARTMENT.Name, TEACHER.Name, TEACHER.IDCode, POST.Name, TEACHER.Tel, TEACHER.Salary, TEACHER.Rise, TEACHER.HireDate, Chief
FROM TEACHER, DEPARTMENT, POST
WHERE TEACHER.ID_Post = POST.ID AND
    TEACHER.ID_Department = DEPARTMENT.ID;
GO

Answer 1

JOIN桌子再TEACHER一次，像这样：

SELECT 
  d.Name, 
  t.Name, 
  t.IDCode, 
  p.Name, 
  t.Tel, 
  t.Salary, 
  t.Rise, 
  t.HireDate, 
  chief.Name 'Chief Name'
FROM TEACHER t 
INNER JOIN TEACHER chief ON t.Chief = chief.ID
INNER JOIN DEPARTMENT d ON t.ID_Department = d.ID
INNER JOIN POST p ON t.ID_Post = p.ID;

并使用 ANS-SQL-92JOIN语法而不是您在查询中使用的旧语法。它们是相同的，但这是推荐的语法。

Answer 2

这应该有效：

SELECT DEPARTMENT.Name, TEACHER.Name, TEACHER.IDCode
    , POST.Name, TEACHER.Tel, TEACHER.Salary, TEACHER.Rise, TEACHER.HireDate, c.Name as ChiefName
    FROM TEACHER
    join DEPARTMENT on TEACHER.ID_Department = DEPARTMENT.ID
    Join POST on TEACHER.ID_Post = POST.ID
    Left Join TEACHER c on c.ID=TEACHER.Chief