select * from table_name
where year(getdate())*12 + month(getdate()) - year(add_date) * 12 + month(add_date) <= 3
where year(getdate())*12 + month(getdate()) - year(add_date) * 12 + month(add_date) <= 3
调试欢乐多
datediff()获取时间差(可以是天,小时,分...等单位)
select * from table_name
where (year(getdate())*12 + month(getdate()) - year(add_date) * 12 - month(add_date)) <= 3
用DateDiff函数