CASE WHEN的用法

select * from TableName
id    idName
1    A
2    B
select  case  id  when 1   then  '在售'  else '售罄' end as 状况 from  TableName
状况
在售
售罄

select case when id=1 then '在售'
when id=2 then '售完' end
as 状况 from TableName

状况
在售
售罄