select 

s,sum(gs) as num,dt from

(select case

when left(Start,2)='XS'then Start else 

left(Start,2) end s,DATEDIFF(ss,ReqTime,EndTime) as gs

,CONVERT(NVARCHAR(10),ReqTime) as dt--ReqTime,EndTime 

from test

where ReqTime is not null

and [ReqTime] between '${FORMAT(kssj,"yyyy-MM-dd 20:00:00")}' and '${FORMAT(jssj,"yyyy-MM-dd 08:00:00")}'

and left(Start,2) !='XS'

--and SUBSTRING(ReqTime,12,2)>='08'and SUBSTRING(ReqTime,12,2)<'20'

) a

group by s,dt

and SUBSTRING(ReqTime,12,2) in('20','21','22','23','24','00','01','02','03','04','05','06','07')

或者

and (SUBSTRING(ReqTime,12,2)<'08' or SUBSTRING(ReqTime,12,2)>='20')