在SQL中使用多个表

Question

我有三张桌子:

department,employee和telephone

employee有列EmpNo,Surname,Firstname和DeptNo.

telephone有列EmpNo和Extension.

department有列DeptNo和DeptName.

我想要的是全名,部门名称和电话分机.

我想我差不多了,但还没有工作.

我的查询

SELECT e.Firstname, e.Surname, d.DeptName, t.Extension
FROM employee AS e
INNER JOIN department AS d
INNER JOIN telephone AS t
ON e.DeptNo = d.DeptNo
ON t.EmpNo = e.EmpNo;

Answer 1

要解决您的问题,请ON在下一个之前移动其中一个子句JOIN

SELECT e.Firstname, e.Surname, d.DeptName, t.Extension
FROM employee AS e
INNER JOIN department AS d
  ON e.DeptNo = d.DeptNo
INNER JOIN telephone AS t
  ON t.EmpNo = e.EmpNo;