Declare @MS as int
Declare @VM as int
Declare @Real as int
Declare @Total as int

set @Total = (select count(*) from v_GS_COMPUTER_SYSTEM)
set @MS = (select count(*) from v_GS_COMPUTER_SYSTEM where Manufacturer0 = 'Microsoft Corporation' )
set @VM = (select count(*) from v_GS_COMPUTER_SYSTEM where Manufacturer0 = 'VMware, Inc.')
set @Real = (select @total - @MS - @VM)

Select
           @Real as 'Real PCs',
           @MS as 'MS Virtual PCs',
           @VM as 'VM Virtual PCs',
           @Total as 'Total'