Athena UNNEST 数组转换为列值

Question

WITH key_value AS
(
    SELECT e
    FROM headers
    CROSS JOIN UNNEST(CAST(json_parse(headers) AS array(json))) t(e)
)
SELECT
    CAST(JSON_PARSE(e) AS map(varchar, varchar)) AS value
FROM
    key_value

{
    "headers": [{
        "key": "Name",
        "value": "xxxx"
    },
    {
        "key": "Email",
        "value": "xxxx"
    },
    {
        "key": "ID",
        "value": "1234"
    },
    {
        "key": "Company",
        "value": "XYZ"
    },
    {
        "key": "Groups",
        "value": "[]"
    },
    {
        "key": "Address",
        "value": "xxxx"
    },
    {
        "key": "State",
        "value": "Log In"
    },
    {
        "key": "Component",
        "value": "xxxx"
    },
    {
        "key": "LastUsed",
        "value": "xxxx"
    }]
}

到目前为止，我已经尝试过这段代码，第一部分似乎有效，它似乎给了我最内在的 JSON 对象，但可以将它们转换为单独的列对象。

我需要将每个标题数组变成一行，其中键作为列，值作为数据。

Answer 1

您可以将第二个unnest（注意简洁的语法）应用于将数据展平为列的地图：

SELECT k, v
FROM key_value,
unnest(CAST(e AS map(varchar, varchar))) as t(k, v)