SQL: Extract from messy JSON nested field with backslashes

Question

I have a table that has some rows with normal JSON and some with escaped values in the JSON field (backslashes)

id	obj
1	{"is_from_shopping_bag":true,"products":[{"price":{"amount":"18.00","currency":"USD","offset":100,"amount_with_offset":"1800"},"product_id":"1234","quantity":1}],"source":"cart"}
2	{"is_from_shopping_bag":"","products":"[{\ "product_id\ ":\ "2345\ ",\ "price\ ":{\ "currency\ ":\ "USD\ ",\ "amount\ ":\ "140.00\ ",\ "offset\ ":100},\ "quantity\ ":1}]"}

(Note: I needed to include a space after the backslashes in the above table so that they would show up in the github generated markdown table -- my actual table does not include those spaces between the backslash and the quote character)

I am doing a sql query in Hive to get the 'currency' field.

Currently I can run

SELECT
    id,
    JSON_EXTRACT(obj, '$.products[0].price.currency')
FROM my_table

Which will give me the correct output for the first row, but gives me a NULL in the second row

id	obj
1	"USD"
2	NULL

What is the best way to get currency field from the second row? Is there a way to clean up the field and remove the backslashes before trying to JSON_EXTRACT the relevant data? I could use REPLACE to swap the '\ ' for '', but is that the most efficient method?

leftjoin · Accepted Answer · 2021-06-11 20:54:50Z

1

Replace \" with " using regexp_replace like this:

regexp_replace(obj,'\\\\"','"')

answered Jun 11, 2021 at 20:54

leftjoin

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