날짜로 요일별 알아내기

SELECT (Apply_Year+Apply_Month+Apply_Day) As '날짜',
   CASE DATEPART(dw, (Apply_Year+Apply_Month+Apply_Day)) 
                  
         WHEN 1 THEN '일'

                  WHEN 2 THEN '월'

                  WHEN 3 THEN '화'

                  WHEN 4 THEN '수'

                  WHEN 5 THEN '목'

                  WHEN 6 THEN '금'

                  ELSE '토'
            END As '요일'

FROM SALE_INFO