Question

I’m working on the adventureworks example database.

I have a table with employee’s, which all have a certain manager. So in the table employee’s there is a column ManagerID.

Also in the table employee there’s a ContactID, which contains the name of that employee.

I would like to have a list with all the managers and their names. How can I pull this off?

The table looks something like

EmployeeID  ContactID  ManagerID
----------  ---------  ---------
    1           21         4
    2           24         4
    3           32         7
    4           34         2
    5           35         2
    6           42         7
    7           44         4

So i’ll need a DISTINCT list of the managerID, and then search for each managerID their appropreate ContactID.

So:
manager of employee 1 is Employee 4 with the ContactID 34.
manager of employee 3 is Employee 7 with the ContactID 44.
manager of employee 4 is Employee 2 with the ContactID 24.

Thanks.

Answer 1

You can do it joining the table myTable with itself matching manager_id’s with employee_id’s

select 
    t.employeeid as employee_id, 
    t.manager_id as manager_id, 
    t2.contact_id as manager_contact_id 
from mytable t left outer join mytable t2 on t.managerid = t2.employeeid