Question

我是SQLite的新手。我想显示每个员工的姓名和他/她经理的姓名。但我对如何将managerID与EmployeeID链接有点困惑？我需要使用子查询吗？

table: Employee
Columns: EmployeeID [pk], EmployeeName, ManagerID

像：

EmployeeID    EmployeeName   ManagerID
  1              Alice          2
  2              Peter         null
  3              John           2
  4              Mary           1

意味着Peter是Alice和John的经理，而Alice是Mary的经理。

SELECT EmployeeName AS Employee, EmployeeName AS Manager
FROM Employee
WHERE

Answer 1

您需要使用LEFT OUTER join加入表格。由于老板没有经理（null），请使用“ifnull”：

select A.EmployeeName as 'EmployeeName', 
   ifnull(B.EmployeeName, 'BOSS') as 'ManagerName' 
   from employee A left outer join employee B 
   on A.managerId = B.employeeId;

SQlite如何在此表中显示员工和经理姓名？

1 个答案: