mysql：case-when-end例子

下面是简单的用法：

case 
    when 字段 
        then 字段等于何值1
        then 字段等于何值2
        ...
        else 字段等于何值3
        end as 新的列名

例子：

select case x.board_id
when '4k' then '4K'
when 'bendi' then '本地'
when 'jiaoyu' then '教育'
when  'shaoer'  then '少儿'
when  'wojia'  then '我+'
when  'xinwen'  then '新闻'
when  'yingshi'  then '影视'
when  'yingyong'  then '应用'
when  'zhibo'  then '直播'
when  'zhuanqu'  then '专区'
when  ''  then '视频小窗口'
else  '' 
end as board_name,x.board_pv,x.board_uv,x.which_date
from info_board_pvuv x