sql 行变列

select * from market//查看原来所有数据

//第一种方式
select
      max(case area when '南京' then num else 0 end) 南京,
      max(case area when '上海' then num else 0 end) 上海,
      max(case area when '无锡' then num else 0 end) 无锡
 from market
 //第二种
 SELECT  *
FROM    ( SELECT   *
          FROM      market
        ) p PIVOT
( max(num) FOR area IN ( [南京],[上海],[无锡] ) ) AS pvt

//第三种

select *
from market PIVOT(max([num]) for [area] in (南京,上海,无锡)) as a