Where 절에 case when 구문을 이용한 between 활용

DECLARE @AAA NVARCHAR(4)
DECLARE @BBB NVARCHAR(4)
SET @FROM_VAL = '0101'
SET @TO_VAL = '0311'

SELECT * FROM FTB_COM
WHERE --CD_COM BETWEEN @AAA AND @BBB

   CD_COM >= CASE WHEN @FROM_VAL = '' OR @FROM_VAL IS NULL

THEN CD_COM ELSE @FROM_VAL END

  AND 

  CD_COM <= CASE WHEN @TO_VAL = '' OR @TO_VAL IS NULL

 THEN CD_COM ELSE @TO_VAL END

ORDER BY CD_COM

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쿼리문 사용이 자연스럽지 못하지만 .. 언젠간 곧..