How to extract elements from Presto ARRAY(MAP(VARCHAR, VARCHAR)) - sql

Question

I have an array of maps and data format is ARRAY(MAP(VARCHAR, VARCHAR)); I'd like to extract "id" and "description" features from this "Item_Details" column:
+-----------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------+--+--+
| Company | Country | Item_Details | | |
+===========+=============+============================================================================================================================================================+==+==+
| Apple | US | [{"created":"2019-09-15","product":"apple watch", "amount": "$7,900"},{"created":"2022-09-19","product":"iPhone", "amount": "$78,300"},{"created":"2021-01-13","product":"Macbook Pro", "amount": "$163,980"}] | | |
| Google | US | [{"created":"2020-07-15","product":"Nest", "amount": "$78,300"},{"created":"2021-07-15","product":"Google phone", "amount": "$178,900"}] | | |
+-----------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------+--+
My expected outputs would be:
+-----------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------+--+--+
| Company | Country | Item_Details | | |
+===========+=============+============================================================================================================================================================+==+==+
| Apple | US | ["product":["apple watch", "iPhone", "Macbook Pro"], "amount":[ "$7,900", "$78,300","$163,980"] | | |
| Google | US | ["product":["Nest", "Google phone"], "amount": "$78,300", "$178,900"] | | |
+-----------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------+--+
or
+-----------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------+--+--+
| Company | Country | Product | Amount | | |
+===========+=============+============================================================================================================================================================+==+==+
| Apple | US | apple watch | $7,900 | | |
| Apple | US | iPhone | $78,300 | | |
| Apple | US | Macbook Pro | $163,980 | | |
...
+-----------+-------------+------------------------------------------------------------------------------------------------------------------------------------------------------------+--+
I tried element_at(Item_Details, 'product') and json_extract_scalar(Item_Details, '$.product') but received error "Unexpected parameters (array(map(varchar,varchar)), varchar(23)) for function element_at. "
Any suggestions is much appreciated! Thank you in advance

Answer 1

For the second one you can unnest the array and access elements of map:
-- sampel data
WITH dataset(Company, Country, Item_Details) AS (
values ('Google', 'US', array[
map(array['created', 'product', 'amount'], array['2019-09-15', 'Nest', '$78,300']),
map(array['created', 'product', 'amount'], array['2019-09-16', 'Nest1', '$79,300'])
])
)
-- query
select Company,
Country,
m['product'] product,
m['amount'] amount
from dataset d,
unnest(Item_Details) as t(m);
Output:
Company
Country
product
amount
Google
US
Nest
$78,300
Google
US
Nest1
$79,300