Question

我有一个像

这样的员工表

emp_id bigint,
reports_to bigint,
emp_name varchar(20),
Constraint [PK_Emp] Primary key (emp_id),
Constraint [FK_Emp] Foreign key (reports_to) references [MSS].[dbo].[Emp]([emp_id])

emp_id         reports_to        emp_name
------         ------       --------------
1              null         Sumanta
2              1            Arpita
3              null         Pradip
4              1            Sujon
5              2            Arpan
6              5            Jayanti

我想让直接或间接向Sumanta或emp_id（1）报告的所有员工，以及层次结构级别，如下所示：

emp_id         hierarchy_level         emp_name
------         ---------------        ----------
2                    1                  Arpita
4                    1                  Sujon
5                    2                  Arpan
6                    3                 Jayanti

我是SQL的新手，无法找到使用的内容或如何获得这些结果。值得存储过程与表值变量，或只是一个Tsql选择查询就足够了。我们非常欢迎任何帮助。

我所做的只是 -

Select Ep.emp_id,ep.emp_eame 
From Emp as E 
Inner Join Emp as Ep on Ep.reports_to=E.Emp_id 
Where E.reports_to=1 or E.emp_id=1;

但这准确到2级，我甚至无法生成hierarchy_level否。任何建议，想法............将是最有帮助的.........

Answer 1

您可以使用递归CTE：

; with  CTE as 
        (
        select  emp_id
        ,       reports_to
        ,       emp_name
        ,       1 as level
        from    Emp
        where   emp_name = 'Sumanta'
        union all
        select  child.emp_id
        ,       child.reports_to
        ,       child.emp_name
        ,       level + 1
        from    Emp child
        join    CTE parent
        on      child.reports_to = parent.emp_id
        )
select  *
from    CTE

Example at SQL Fiddle.

Answer 2

使用Common_Table_Expression我们可以这样写

WITH Employee_CTE(employeeid,hierarchy_level,name) AS  
(  
   SELECT employeeid,1 as level,name from employee where employeeid=1 
   UNION ALL  
   SELECT e.employeeid,level +1, e.name 
   from employee e   
   INNER JOIN Employee_CTE c ON e.employeeid = c.managerid  
)  
SELECT * FROM Employee_CTE order by employeeid

获取直接或间接向员工报告的所有员工，层次结构级别为no

2 个答案: