[英]How to pivot rows into columns in AWS Athena?
我是AWS Athena的新手并试图将一些行转换为列,类似于此StackOverflow帖子中的最佳答案。
但是,当我尝试时:
SELECT column1, column2, column3
FROM data
PIVOT
(
MIN(column3)
FOR column2 IN ('VALUE1','VALUE2','VALUE3','VALUE4')
)
我收到错误: mismatched input '(' expecting {',', ')'} (service: amazonathena; status code: 400; error code: invalidrequestexception
有谁知道如何实现我想在AWS Athena中实现的目标?
扩展@kadrach的答案。 假设这样的表
uid | key | value1 | value2
----+-----+--------+--------
1 | A | 10 | 1000
1 | B | 20 | 2000
2 | A | 11 | 1001
2 | B | 21 | 2001
单列PIVOT的工作原理如下
SELECT
uid,
kv1['A'] AS A_v1,
kv1['B'] AS B_v1
FROM (
SELECT uid, map_agg(key, value1) kv1
FROM vtable
GROUP BY uid
)
结果:
uid | A_v1 | B_v1
----+------+-------
1 | 10 | 20
2 | 11 | 21
多列PIVOT的工作原理如下
SELECT
uid,
kv1['A'] AS A_v1,
kv1['B'] AS B_v1,
kv2['A'] AS A_v2,
kv2['B'] AS B_v2
FROM (
SELECT uid,
map_agg(key, value1) kv1,
map_agg(key, value2) kv2
FROM vtable
GROUP BY uid
)
结果:
uid | A_v1 | B_v1 | A_v2 | B_v2
----+------+------+------+-----
1 | 10 | 20 | 1000 | 2000
2 | 11 | 21 | 1001 | 2001
我在使用PIVOT功能时遇到了同样的问题。 但是我使用转向方式来获取类似的格式数据集:
select
columnToGroupOn,
min(if(colToPivot=VALUE1,column3,null)) as VALUE1,
min(if(colToPivot=VALUE2,column3,null)) as VALUE2,
min(if(colToPivot=VALUE3,column3,null)) as VALUE3
from
data
group by columnToGroupOn
你可以使用map_agg
在Athena中进行map_agg
PIVOT
。
SELECT
uid,
kv['c1'] AS c1,
kv['c2'] AS c2,
kv['c3'] AS c3
FROM (
SELECT uid, map_agg(key, value) kv
FROM vtable
GROUP BY uid
) t
信用到这个网站 。 不幸的是,我没有找到一种聪明的方法来以这种方式进行多列透视(我嵌套查询,这不是很漂亮)。
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