Нещо подобно?
select sum(case when ws.ID_WorkflowType = 1 then 1 else 0 end) as cntCM_PRWK
, sum(case when ws.ID_WorkflowType = 3 then 1 else 0 end) as cntCM_CMQ
from dbo.CaseWorkflow cw
join vew_CasePersonnelSystemIDs vcps on cw.ID_Case = vcps.ID_Case
join dbo.WorkflowStates ws on ws.ID_WorkflowState = cw.ID_WorkflowState
where CMSUID = @nSUID