How to add a column via a query which counts the total rows with a specific criteria in a table with circular relationship in MS ACCESS 2007
- by Xaqron
I have a simple table "Employees" with this fields:
ID, ParentID, Name
ParentID is Nullable since an employee may have no Manager.
This table has a one-to-many relationship with itself:
ID --one--to--many--> ParentID
Now I want a query which returns this columns:
Name, Count of rows where their ParentID equals to the current row ID (the row is the manager of that rows)
Sample Table:
ID | ParentID | Name
======================
 1 |     0    | John
----------------------
 2 |     1    | Bob
----------------------
 3 |     1    | Alice
----------------------
 4 |     3    | Jack
This way I can find an employee is the manager of how many other employees.
The result should be something like this:
Name  | Count of Employees
==========================
John  |   2
--------------
Bob   |   0
--------------
Alice |   1
--------------
Jack  |   0
How can I achieve this in MS ACCESS 2007?
* I have tried built-in query builder without any success.