if object_id('people') is not null
    drop table people
go

create table people(ID int, Sex int)
go

insert into people
select 1, 1 union all
select 2, 1 union all
select 3, 2 union all
select 4, 2
go

select ID, Sex=(case Sex 
                when 1 then '男' 
                when 2 then '女'
                else ''
                end)            
from people

/*
ID          Sex
----------- ----
1           男
2           男
3           女
4           女
*/

------解决方案--------------------
探讨


select case when 性别 = 1 then '男' when  性别 = 2 then '女' else '不男不女' end from tb


------解决方案--------------------
select  case when 1 then 男 else  女 end
from  tb

------解决方案--------------------
探讨


select case when 性别 = 1 then '男' when  性别 = 2 then '女' else '不男不女' end from tb


------解决方案--------------------
select case when 性别 = 1 then '男' when 性别 = 2 then '女' else '待定' end from tb

------解决方案--------------------
case 性别 when 1 then '男' when 2 then '女' end

------解决方案--------------------
探讨


select case when 性别 = 1 then '男' when  性别 = 2 then '女' else '不男不女' end from tb