如何在 presto sql 中取消嵌套 varchar 数组

Question

我有一个包含 varchar 值的列 description，我想取消嵌套以将 stallid 和 itemid 作为单独的列检索。

[{"stallid":6771032,"itemid":12232},{"stallid":6771033,"itemid":12233}]

我尝试了以下语法，但它不起作用。

select JSON_EXTRACT_SCALAR(description) from tableA

有人知道怎么做吗？

Answer 1

select item['stallid'] as stallid, item['itemid'] as itemid
from 
(select cast(json_parse('[{"stallid":6771032,"itemid":12232},{"stallid":6771033,"itemid":12233}]') as array<MAP<VARCHAR, VARCHAR>>) as items) CROSS JOIN UNNEST(items) AS items(item);

 stallid | itemid 
---------+--------
 6771032 | 12232  
 6771033 | 12233

https://trino.io/docs/current/functions/json.html#json_parse

如何在 presto sql 中取消嵌套 varchar 数组

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