생산실적 관련된 테이블일 듯한 느낌이 -,-;;;

아침에 야<->주 교대 이후 시점을 하루의 시작으로 보는 형태죠?

(아니라면 미안합니다^^;;)

하기 쿼리 참고하세요...

---쿼리시작---

;with tblA(Date) As
(
      Select '2016-02-11 09:00:00' Union All
      Select '2016-02-11 20:00:00' Union All
      Select '2016-02-12 02:00:00' Union All                 
      Select '2016-02-12 08:00:00' Union All                  
      Select '2016-02-12 08:29:59' Union All                  
      Select '2016-02-12 08:30:00' Union All                  
      Select '2016-02-12 20:30:00'
)
,tblB(Date,Date2) As
(
      Select
             a.Date
            ,Convert(Char(20)
                     ,
                                (
                                   Case When Convert(Integer,Replace(Right(Rtrim(a.Date),8),':','')) >= 83000
                                           Then LEFT(a.Date,10)
                                        Else
                                             DATEADD(day,-1,Left(a.Date,10))
                                   End
                                 )
                     ,120
                    )
        From tblA a
 )
      Select a.Date
            ,a.Date2
            ,  SubString(a.Date2,3,2)
             + SubString(a.Date2,6,2)
             + SubString(a.Date2,9,2)
                As Date3
        From tblB a
---쿼리끝---       

시간연산을 이용하셔도 괜찮을것 같습니다.

;with tblA(Date) As
(
      Select '2016-02-11 09:00:00' Union All
      Select '2016-02-11 20:00:00' Union All
      Select '2016-02-12 02:00:00' Union All                 
      Select '2016-02-12 08:00:00' Union All                  
      Select '2016-02-12 08:29:59' Union All                  
      Select '2016-02-12 08:30:00' Union All                  
      Select '2016-02-12 20:30:00'
)
select CONVERT(varchar, DATEADD(MINUTE, -510, date), 12) as date2
from tblA