How to delete a jsonb item in a nested psql array - sql

Question

I have a table users:
`CREATE TABLE users(
id SERIAL PRIMARY KEY NOT NULL,
username TEXT UNIQUE,
saved_articles JSONB[],
)`
I added a user like so:
"INSERT INTO users (username, saved_articles) VALUES (?, array[]::jsonb[]) RETURNING id, username, saved_articles"
After adding some articles I have this data shape:
{ id: 1,
username: 'test',
saved_articles:
[ { url: 'test',
title: '',
author: '',
source: '',
content:"",
urlToImage: ''
},
{ url: 'not-test',
title: '',
author: '',
source: '',
content:"",
urlToImage: ''
}
]
}
I want to be able to delete a specific item from the saved_articles array based on the url value.
For example, if my url value is 'test', after running the query my data should look like:
{ id: 1,
username: 'test',
saved_articles:
[ { url: 'not-test',
title: '',
author: '',
source: '',
content:"",
urlToImage: ''
}
]
}

Answer 1

First of all, the format of JSONB columns's value should be fixed. That might be tested through CASTing AS JSONB by a SELECT statement such as
SELECT '{ "id": "1",
"username": "test",
"saved_articles":
[ { "url": "test",
"title": "",
"author": "",
"source": "",
"content":"",
"urlToImage": ""
},
{ "url": "not-test",
"title": "",
"author": "",
"source": "",
"content":"",
"urlToImage": ""
}
]}'::jsonb
whether returns error or not.
Then, remove the desired element from the array by use of jsonb_array_elements(json_data -> 'saved_articles') function together with ->> 'url' != 'test' criteria.
And then reconstruct the array by remaining elements by using jsonb_build_array and jsonb_object_agg.
At the last step concatenate the part which doesn't contain that individual array extracted by json_data #- '{saved_articles}' :
SELECT js0||jsonb_object_agg( 'saved_articles', js1 ) AS "Result JSONB"
FROM
(
SELECT json_data #- '{saved_articles}' AS js0, jsonb_build_array( js ) AS js1
FROM tab
CROSS JOIN jsonb_array_elements(json_data -> 'saved_articles') js
WHERE js ->> 'url' != 'test'
) q
GROUP BY js0
Demo