ms sql case 用法

select name,

( case  when classname='juhui' then '时尚聚会' 
                when classname= 'dianying' then '电影'
               when classname='yanchu' then '演出'
               when classname='gongyi' then '公益'
               when classname='yishenghuo' then '夜生活'
               when classname='qita' then '其他'
               when classname='zhanhui' then '展会'
                when classname='yundong' then '运动'
end )  as  classname,                                                               //需要括起来 并且命名为classname 否则 这列将是无名列

password from student