Question

我需要一些我需要编写的查询帮助

检索处理不受其部门控制的项目的员工的名字和姓氏。还显示项目的名称，员工的部门编号以及项目控制部门的编号。（所有这些都应该显示在相同的结果表中。）以升序的alpha顺序显示结果（按姓氏，然后是名字，然后项目名称）。

表：

Employee(Fname,Lname,SSN,DepartNum)
Department(Dname,Dnumber)
Project(Pname,Pnumber,DepNum)
WorksOn(EmpSSN,ProjNum)

查询的列标题：Fname，Lname，Pname，E_DNUM，P_DNUM

SELECT Fname,Lname,Project.Pname,(Employee.DepartNum) AS E_DNUM (Project.DepNum) AS P_DNUM
FROM Department,
    (SELECT *
    FROM Employee
    LEFT JOIN WorksOn
      LEFT JOIN Project
      ON Project.Pnumber = WorksOn.Pnum
    ON Employee.SSN = WorksOn.ESSN)
WHERE Project.DepNum = Department.Dnumber
AND Employee.DepartNum <> Department.Dnumber;

Answer 1

如果我没有遗漏某些内容，您可以加入所有表并应用条件Employee.DepartNum <> Project.DepNum来获得您想要的结果：

select Fname,Lname,Pname, Employee.DepartNum E_DNUM,Project.DepNum P_DNUM
from Employee
join WorksOn on WorksOn.EmpSSN = Employee.SSN
join Project on WorksOn.ProjNum = Project.Pnumber
join Department on Project.DepNum = Department.Dnumber
where Employee.DepartNum <> Project.DepNum

复杂连接和选择查询

1 个答案: