SELECT * FROM P_BBXXB where substring(pxtime,12,10) > getdate()

------解决方案--------------------
  /// <summary>
   ///  
   /// </summary>
   /// <param name="str">要截取的字符串</param>
   /// <param name="start">开头</param>
   /// <param name="last">结束</param>
   /// <returns></returns>
   public static string yuan(string str, string start, string last)
   {

       if (str.ToLower().IndexOf(start.ToLower()) >= 0)
       {
           str = str.Substring(str.ToLower().IndexOf(start.ToLower()) + start.Length, str.Length - str.ToLower().IndexOf(start.ToLower()) - start.Length); str = str.Substring(0, str.ToLower().IndexOf(last.ToLower()));
           return str;
       }
       else
       {
           return str = "";
       }
   }
yuan.("2010-12-04~2010-12-13","2","~");
这就截取出2010-12-13