How to remove all \ from nested json in SQL Redshift? - sql

Question

I've got some problems with extracting values from nested json values in column.
I've got a column of data with values that looks almost like nested json, but some of jsons got \ between values and I need to clean them.
JSON looks like this:
{"mopub_json":
"{\"currency\":\"USD\",
\"country\":\"US\",
\"publisher_revenue\":0.01824}
"}
I need to get currency and publisher revenue as different columns and try this:
SET json_serialization_enable TO true;
SET json_serialization_parse_nested_strings TO true;
SELECT
JSON_EXTRACT_PATH_TEXT(column_name, 'mopub_json', 'publisher_revenue') as revenue_mopub,
JSON_EXTRACT_PATH_TEXT(column_name, 'mopub_json', 'currency') as currency_mopub
FROM(
SELECT replace(column_name, "\t", '')
FROM table_name)
I receive the next error:
[Amazon](500310) Invalid operation: column "\t" does not exist in events
When I'm trying this:
SET json_serialization_parse_nested_strings TO true;
SELECT
JSON_EXTRACT_PATH_TEXT(column_name, 'mopub_json', 'publisher_revenue') as revenue_mopub,
JSON_EXTRACT_PATH_TEXT(column_name, 'mopub_json', 'currency') as currency_mopub
FROM(
SELECT replace(column_name, chr(92), '')
FROM table_name)
I receive
Invalid operation: JSON parsing error
When I'm trying to extract values without replacing , I'm receiving empty columns.
Thank you for your help!

Answer 1

So your json isn't valid. JSON doesn't allow multiline text strings but I expect that the issue. Based on your query I think you don't want a single key and string but the whole structure. The reason the that quotes are backslashed is because they are inside a string. The json should look like:
{
"mopub_json": {
"currency": "USD",
"country": "US",
"publisher_revenue": 0.01824
}
}
Then the SQL you have should work.