Get all employee who directly or indirectly reports to an employee, with hierarchy level no

Question

I have a Employee table like

emp_id bigint,
reports_to bigint,
emp_name varchar(20),
Constraint [PK_Emp] Primary key (emp_id),
Constraint [FK_Emp] Foreign key (r         


        

Answer 1

Using Common_Table_Expression we can write like this

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  

Answer 2

You could use a recursive 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.