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

Posted by Xaqron on Stack Overflow See other posts from Stack Overflow or by Xaqron
Published on 2012-08-29T21:12:58Z Indexed on 2012/08/29 21:38 UTC
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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.

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