查询雅典娜时将结构转换为json [英] converting a struct to a json when querying athena
问题描述
我有一个雅典娜表,我没有创建或管理它,但可以查询。字段之一是结构类型。为了便于说明,我们假设它看起来像这样:
my_field struct< a:string,
b:string ,
c:struct< d:string,e:string>
>
现在,我知道如何查询此结构中的特定字段。但是在我的查询之一中,我需要提取完整的结构。所以我只用:
从my_table
,结果看起来像一个字符串:
{a = aaa,b = bbb,c = {d = ddd,e = eee}}
我想得到结果作为json字符串:
{ a: aaa, b: bbb, c: { d: ddd, e: eee}}
此字符串将然后被另一个应用程序处理,这就是为什么我需要json格式的原因。
我该如何实现?
编辑:
更妙的是,有没有一种方法可以使结构扁平化呢?因此结果将如下所示:
a | b | c.d | c.e |
-------------------------------
aaa | bbb | ddd | eee |
您可以直接引用带有<$ c的嵌套字段$ c> parent_field.child_field 表示法。尝试:
SELECT
my_field,
my_field.a,
my_field.b,
my_field.cd,
my_field.ce
FROM
my_table
I have an athena table which I did not create or manage, but can query. one of the fields is a struct type. for the sake of the example let's suppose it looks like this:
my_field struct<a:string,
b:string,
c:struct<d:string,e:string>
>
Now, I know how to query specific fields within this struct. But in one of my queries I need to extract the complete struct. so I just use:
select my_field from my_table
and the result looks like a string:
{a=aaa, b=bbb, c={d=ddd, e=eee}}
I want to get the result as a json string:
{"a":"aaa", "b":"bbb","c":{"d":"ddd", "e":"eee"}}
this string will then be processed by another application, this is why i need it in json format.
How can I achieve this?
EDIT: Better still, is there a way to query the struct in a way that flattens it? so the result would look like:
a | b | c.d | c.e |
-------------------------------
aaa | bbb | ddd | eee |
You can directly reference nested fields with a parent_field.child_field
notation. Try:
SELECT
my_field,
my_field.a,
my_field.b,
my_field.c.d,
my_field.c.e
FROM
my_table
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