SCCM Device Collection from AD security group

This query will create an SCCM device colletion from an AD security group
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 where SMS_R_System.SystemGroupName = "contoso\\ADSecurityGroupName"

you will replace the name of the security group in the query with your own, using a double backslash as an escape character to put in a single backslash.