Querying over PostgreSQL JSONB column - sql

Question

I have a table "blobs" with a column "metadata" in jsonb data-type,
Example:
{
"total_count": 2,
"items": [
{
"name": "somename",
"metadata": {
"metas": [
{
"id": "11258",
"score": 6.1,
"status": "active",
"published_at": "2019-04-20T00:29:00",
"nvd_modified_at": "2022-04-06T18:07:00"
},
{
"id": "9251",
"score": 5.1,
"status": "active",
"published_at": "2018-01-18T23:29:00",
"nvd_modified_at": "2021-01-08T12:15:00"
}
]
}
]
}
I want to identify statuses in the "metas" array that match with certain, given strings. I have tried the following so far but without results:
SELECT * FROM blobs
WHERE metadata is not null AND
(
SELECT count(*) FROM jsonb_array_elements(metadata->'metas') AS cn
WHERE cn->>'status' IN ('active','reported')
) > 0;
It would also be sufficient if I could compare the string with "status" in the first array object.
I am using PostgreSQL 9.6.24

Answer 1

for some clarity I usually break code into series of WITH statements. My idea for your problem would be to use json path (https://www.postgresql.org/docs/12/functions-json.html#FUNCTIONS-SQLJSON-PATH) and function jsonb_path_query.
Below code gives a list of counts, I will leave the rest to you, to get final data.
I've added ID column just to have something to join on. Otherwise join on metadata.
Also, note additional " in where condition. Left join in blob_ext is there just to have null value if metadata is not present or that path does not work.
with blob as (
select row_number() over()"id", * from (VALUES
(
'{
"total_count": 2,
"items": [
{
"name": "somename",
"metadata": {
"metas": [
{
"id": "11258",
"score": 6.1,
"status": "active",
"published_at": "2019-04-20T00:29:00",
"nvd_modified_at": "2022-04-06T18:07:00"
},
{
"id": "9251",
"score": 5.1,
"status": "active",
"published_at": "2018-01-18T23:29:00",
"nvd_modified_at": "2021-01-08T12:15:00"
}
]
}
}
]}'::jsonb),
(null::jsonb)) b(metadata)
)
, blob_ext as (
select bb.*, blob_sts.status
from blob bb
left join (
select
bb2.id,
jsonb_path_query (bb2.metadata::jsonb, '$.items[*].metadata.metas[*].status'::jsonpath)::character varying "status"
FROM blob bb2
) as blob_sts ON
blob_sts.id = bb.id
)
select bbe.id, count(*) cnt, bbe.metadata
from blob_ext bbe
where bbe.status in ('"active"', '"reported"')
group by bbe.id, bbe.metadata;

Answer 2

A way is to peel one layer at a time with jsonb_extract_path() and jsonb_array_elements():
with cte_items as (
select id,
metadata,
jsonb_extract_path(jx.value,'metadata','metas') as metas
from blobs,
lateral jsonb_array_elements(jsonb_extract_path(metadata,'items')) as jx),
cte_metas as (
select id,
metadata,
jsonb_extract_path_text(s.value,'status') as status
from cte_items,
lateral jsonb_array_elements(metas) s)
select distinct
id,
metadata
from cte_metas
where status in ('active','reported');