select dateadd(month,-24,'2002-12-14')
---------------------^^^减
select dateadd(day,-24,'2002-12-14')
----------------^^^天或year年select datediff(day,'2001-1-1','2002-1-1') 天
select datediff(month'2001-1-1','2002-1-1') 月
select datediff(year,'2001-1-1','2002-1-1') 年
---------------------^^^减
select dateadd(day,-24,'2002-12-14')
----------------^^^天或year年select datediff(day,'2001-1-1','2002-1-1') 天
select datediff(month'2001-1-1','2002-1-1') 月
select datediff(year,'2001-1-1','2002-1-1') 年
select dateadd(day,-10,'2003-04-14')2003-04-14’减去‘2003-04-04’得到10天:
select datediff(day,'2003-04-04','2003-04-14')