CREATE FUNCTION [dbo].[UF_COMMON_USER_SELETE_SPLIT] (
       @Param NVARCHAR(1000)
       ,@Delimiter CHAR(1)
       )RETURNS @Return TABLE
       (
   idx INT IDENTITY(1,1) Primary Key,
   value NVARCHAR(Max)
       )
AS
BEGIN
 WHILE charindex(@Delimiter, @Param) <> 0 OR Len(rtrim(@Param)) > 0
 BEGIN
      If (charindex(@Delimiter, @Param) = 0)
   BEGIN
  INSERT INTO @Return VALUES(@Param)
  SET @Param = ''
   END
   ELSE
   BEGIN
  INSERT INTO @Return VALUES(SubString(@Param, 0, charindex(@Delimiter, @Param)))
  SET @Param = SubString(@Param, CharIndex(@Delimiter, @Param) + 1, len(@Param))
   END
 END
    RETURN 
END

실행
SELECT value from [dbo].[UF_COMMON_USER_SPLIT]('A,B',',')