SCCM 2012 - Exchange Servers Collection

Hi guys,

I have a collection that should list all Exchange Servers, but it shows zero members.
The query is the following

select SMS_R_SYSTEM.ResourceID,SMS_R_SYSTEM.ResourceType,SMS_R_SYSTEM.Name,SMS_R_SYSTEM.SMSUniqueIdentifier,SMS_R_SYSTEM.ResourceDomainORWorkgroup,SMS_R_SYSTEM.Client from SMS_R_System inner join SMS_G_System_SERVICE on  SMS_G_System_SERVICE.ResourceId = SMS_R_System.ResourceId  where SMS_G_System_SERVICE.Name like "Microsoft Exchange%"

Do you think the query is wrong ?

I'm not an SCCM expert. Is there a way to debug these queries in a simple manner ?

Thanks in advance