The question came up recently on how to identify which collections are based on Active Directory OU membership in Microsoft System Center Configuration Manager (SCCM) Current Branch
There are tons of guides on how to setup a collection based on OU membership.. but now that you have.. how many have you created?
This is quite simple direct SQL query:
SELECT [CollectionID] ,[RuleName] ,[QueryID] ,[QueryExpression] ,[LimitToCollectionID] FROM [SMS_ABC].[dbo].[v_CollectionRuleQuery] where QueryExpression like ‘%System_OU%’
* not all collection memberships need to be based on System OU. Varitations will be needed based on requirements
* The above query is based on a view. If you want to see the SQL you would query the table Collection_Rules_SQL
The SQL table Collection_Rules_SQL also has the WQL versions of the same query. This is extremely useful for figuring out the SQL tables involved with any WQL query from collections or the Query node. You can also get this translation from the SMSProv.log file but that is like searching for a needle in a hay stack while the hack stack is getting bigger and may disappear in a roll over.
A nice bit of documentation at Creating Custom Reports by Using SQL Server Views in System Center 2012 Configuration Manager
Otherwise, happy spelunking!