DATEDIFF()函数 返回两个日期之间的时间 格式SELECT DATEDIFF(day,'2008-12-29','2008-12-30') AS DiffDate结果:1SELECT DATEDIFF(day,'2008-12-30','2008-12-29') AS DiffDate结果:-1配合ABS() 函数使用 返回一个数值绝对值SELECT ABS(DATEDIFF(day,'2008-12-30','2008-12-29')) AS DiffDate结果:1