T-Sql如何按案例过滤

Question

如何根据具体情况进行过滤？

select * from address
where streetnum > 1000 only when state = MI otherwise select everything else

或

select * from address
where case when state = MI then streetnum > 1000

Answer 1

从address获取所有行，但当state为'MI'时，streetnum必须大于1000。

select * from address
where streetnum > 1000 or state <> 'MI'

如果您想使用case，可能需要检查多个值。

select *
from address
where case state
       when 'MI' then 1000
       when 'MA' then 1000
      else 0
      end < streetnum

如果所有州都有相同的值（1000），那就与此相同。

select * 
from address
where streetnum > 1000 or state not in ('MI', 'MA')

Answer 2

如果我正确地解释了你的问题，那么......

select * from address 
where state <> 'MI' or (state = 'MI' and streetnum > 1000)