我有一张表tb:ApplyID,ApplyDate,=================================John,2008-01-2312:00:01Joe,2008-01-2312:00:02Mary,2008-01-2312:00:02Snoopy,2008-01-2312:00:06Snoopy,2008-01-2312:00:07Snoopy,2008-01-2312:00:11John,2008-01-2312:00:21我想计算每一行在接下来的5秒内有多少行。输出如下:ApplyID,ApplyDate,Sessions====================