判断日期段是否交叉

CREATE FUNCTION dbo.f_SKX_IsDataCross  
    (  
      @fromDate DATETIME ,  
      @toDate DATETIME ,  
      @startDate DATETIME ,  
      @endDate DATETIME  
    )  
RETURNS INT  
  
AS   
BEGIN  
    DECLARE @ret INT  
    IF ( DATEDIFF(DAY, @fromDate, @endDate) >= 0 AND DATEDIFF(DAY, @endDate, @toDate) >= 0 )   
        SET @ret = 1  
    IF ( DATEDIFF(DAY, @startDate, @toDate) >= 0 AND DATEDIFF(DAY, @toDate, @endDate) >= 0 )   
        SET @ret = 1  
    IF ( @ret IS NULL )   
        SET @ret = 0  
    RETURN @ret  
END