select DATEDIFF(day,GETDATE(), last_test_date） from equip_regular_check order by 1

------解决方案--------------------
可以,你试试下面语句,不过按你的语句得出的是负数,我改下.

SELECT DATEDIFF(DAY,last_test_date,GETDATE()) AS RemainDay FROM equip_regular_check
ORDER BY RemainDay.

你试试

------解决方案--------------------

SQL code
select *,datediff(dd,getdate(),last_test_date) as 剩余天数 
from equip_regular_check
order by datediff(dd,getdate(),last_test_date) asc

------解决方案--------------------
SQL code

select 
    datediff(day,getdate(),last_test_date) as 剩余天数
from equip_regular_check order by 1