Question

我从Hackerrank.com遇到了这个sql挑战样本输入：

select * from occupation

示例输出：

Name        Occupation     
samantha    doctor
jenny       doctor
julia       actor
maria       actor
jane        actor
meera       singer
priya       singer
ashley      professor
ketty       professor
christeen   professor

输出应该是:(医生，教授，歌手，演员也按名称命名）

jenny       ashley         meera       jane
samantha    christeen      priya       julia
null        ketty          null        maria

我试过的是：

SELECT DECODE(occupation,'doctor',name,NULL   ),DECODE(occupation,'professor',name,NULL),DECODE(occupation,'singer',name,NULL)  ,
DECODE(occupation , 'actor',name,NULL)
FROM occupation ;

但它并没有给我想要的结果。我也试过这个：

SELECT oc1.name ,
oc2.name,oc3.name,oc4.name
FROM
(SELECT name,occupation FROM occupation WHERE occupation = 'doctor'
) oc1 ,
(SELECT name,occupation FROM occupation WHERE occupation = 'actor'
) oc2 ,
(SELECT name,occupation FROM occupation WHERE occupation = 'singer') oc3,
(SELECT name,occupation FROM occupation WHERE occupation = 'professor')oc4  ,   occupation oc

WHERE 
oc1.occupation= oc.occupation(+)
and oc2.occupation = oc.occupation(+)
AND oc3.occupation       = oc.occupation(+)
AND oc4.occupation       = oc.occupation(+);

但它会提供重复记录。有人可以帮助我吗

由于

Answer 1

使用PIVOT：

SELECT doctor, professor, singer, actor
FROM   (
  SELECT o.*,
         ROW_NUMBER() OVER ( PARTITION BY occupation ORDER BY name ) AS rn
  FROM   occupation o
)
PIVOT ( MAX( name ) FOR Occupation IN (
  'doctor'    AS doctor,
  'actor'     AS actor,
  'singer'    AS singer,
  'professor' AS professor
) )
ORDER BY rn;

如何将单个表视为sql中的多个表

1 个答案: