Question

如果我有一个表Employee在哪里
EmployeeID，
EmployeeName，
FirstName，
LastName，
ManagerID，
ManagerName

此处ManagerID也有EmployeeID。

经理下的员工工作。

如何从表Employee中找到
FirstName，
EmployeeName，
ManagerName

一位经理不超过6名员工。

Answer 1

SELECT FirstName,EmployeeName, ManagerName
FROM Employee e
WHERE e.ManagerID IN
(
    SELECT ManagerID
    FROM Employee 
    GROUP BY ManagerID
    HAVING COUNT(*) <= 6

)

Answer 2

/ *考虑到可能有顶级员工，其中经理ID为空。 MSSQL中的代码* /

SELECT FirstName, EmployeeName, ManagerName 
FROM Employee e INNER JOIN 
(
    SELECT ManagerId 
    FROM Employee 
    WHERE ManagerId IS NOT NULL 
    GROUP BY ManagerId
    HAVING COUNT(*) <= 6  
) t  
ON (e.ManagerId = t.ManagerId OR e.ManagerId IS NULL);

/ *如果我们不关心经理ID是否为空，那么* /

SELECT FirstName, EmployeeName, ManagerName 
FROM Employee e INNER JOIN 
(
    SELECT ManagerId 
    FROM Employee 
    GROUP BY ManagerId
    HAVING COUNT(*) <= 6  
) t  
ON (e.ManagerId = t.ManagerId);

我如何找到一个表

2 个答案: