I listed the number of the helpdesk ticket and the count of the child tickets in this simple query. Hope this helps...

SELECT hd1.workitem_link_parent_number AS Parent,   Count(hd1.workitem_number) AS [Count of Children]  
FROM dbo.HD_workitem_current_view AS hd1   
WHERE NOT(hd1.workitem_link_parent_number = 0)  
GROUP BY hd1.workitem_link_parent_number  
ORDER BY hd1.workitem_link_parent_number

Thank you for your reply NormalC
This is exactly what i'm after.

Glad I could help.