Another easy query. I threw this one together to retrieve Dell Service Tag numbers from staff laptops:

select
SMS_R_System.Name, SMS_G_System_PC_BIOS.SerialNumber from
SMS_R_System inner join SMS_G_System_PC_BIOS on
SMS_G_System_PC_BIOS.ResourceId = SMS_R_System.ResourceId

Which returns the system names and their bios serial numbers AKA service tags.