从日期中添加或减去指定时间间隔

　　DATEADD：从日期中添加或减去指定时间间隔,举例:有以下5条数据

        1、begin                                                                        end

         2008.04.01 08:17                                                    2008.04.01 08:23

         2008.04.01 09:07                                                    2008.04.02 08:25 

         2008.04.03 07:05                                                     2008.04.03 07:08

         2008.04.02 07:05                                                     2008.04.03 07:08

         2008.04.05 07:05                                                     2008.04.05 07:08

就以上5条数据，现在我们想达到的效果是从以上5条数据中选出(end-begin)<=5分钟的记录,那么我们使用该语句:select * from ea where DATEADD(mi,5,begin)>=end(备注：这条命令无法计算出一分钟内的数据,所以还要搭配这条命令才算完美:select * from ea where begin=end执行后得到的记录是

        2、begin                                                                        end

         2008.04.01 08:17                                                    2008.04.01 08:23

         2008.04.03 07:05                                                    2008.04.03 07:08

         2008.04.05 07:05                                                    2008.04.05 07:08

最后关于DATEADD的具体用法请朋友们google一下