//在DataView中排序
            strSql += strWhere + "  ";

            strSql += " and Pmn_ExecutePlanDate>getdate()";
  
            strSql += " and getdate()< DATEADD(dd,-Pmn_PReTimeSpan,Pmn_ExecutePlanDate)";
            //條件判斷
DATEDIFF(datepart,   startdate,   enddate)

一下是diff的參數
Datepart   Abbreviations  
year   yy,   yyyy  
quarter   QQ,   q  
month   mm,   m  
dayofyear   dy,   y  
day   dd,   d  
week   wk,   ww  
hour   hh  
minute   mi,   n  
second   ss,   s  
millisecond   ms