Oracle SQL-Query解析

Question

我有一张这样的表：

eno   name        loc       flag
1    penchal      pune      old
2    penchal      mumbai    current
3    srinivas     hyd       curent
4    mahesh       chenai    current

我想这样说：

Name       oldlocation   newlocation
penchal    pune          mummbai
srinivas   null          hyd
mahesh     null          chennai

请你帮我解决一下如何在oracle sql中为这个场景编写查询;
寻找回复

Answer 1

SELECT  Name,
        MAX(CASE WHEN flag = 'old' THEN loc ELSE NULL END) AS oldlocation,
        MAX(CASE WHEN flag = 'current' THEN loc ELSE NULL END) AS newlocation
FROM    tableName
GROUP   BY Name

Answer 2

SELECT name
     , MAX(DECODE(flag,'old',loc))     oldlocation
     , MAX(DECODE(flag,'current',loc)) newlocation
FROM   tableName
GROUP BY name