Question

我正在尝试从数据库中检索两条记录，检索当前部门和负责该部门的部门。

例如，部门ID 13由部门ID 18管理

select dm.* from TblDepartment d 
join TblDepartment dm 
on d.ManagedBy = dm.id or d.id = dm.ManagedBy
where d.id = 13

我需要使用哪个联接来检索部门13和部门18的部门信息的详细信息？

Answer 1

两行

select 'Dept' as [type], * from 
TblDepartment d 
where d.id = 13
union all
select ' managed by' as [type], * from 
TblDepartment d 
where d.id = 18

或者使用连接和一个输入：

select 'Dept' as [type], * from 
TblDepartment d 
where d.id = 13
union all
select ' managed by' as [type], m.* from 
TblDepartment d 
join TblDepartment m on d.ManagedBy = m.id and d.id = 13

Answer 2

尝试以下方法：

select d.id Dept_Id, d.ManagedBy 
from 
    TblDepartment d 
where
    d.id = 13
union
select dm.id Dept_Id , dm.ManagedBy
from 
    TblDepartment d 
inner 
    join TblDepartment dm 
on  d.ManagedBy = dm.id
where 
    d.id = 13

SQL Join检索选定的记录和where子句

2 个答案: