Display all managers and employees without a manager

Question

I have a table in SQL Server 2008 that for explanation purposes contains, ID, Employee and ManagerID.

eg:

ID  Employee  ManagerID
1   A        NULL
2   B        2
3   C        2

I want to write a query that returns all non related ManagerID's and ID's where ManagerID is equal to the ID.

The result should look like this,

ID  Employee    ManagerID
1   A           NULL
2   B           2

In essence no managers can be managers of managers.

At first I thought that it would be simple using a SELF Join and an EXCLUDE SQL statement however I cannot get this to work. I would prefer not to USE the EXCLUDE statement as my actual table has more columns and related data that I would like to return.

If you could help, I would be grateful.

Answer 1

select employee, managerid
from your_table
where managerid is null 
or managerid = id