Sum of column values ​inside Json array with group by - sql

Question

I have next Django model.
class StocksHistory(models.Model):
wh_data = models.JsonField()
created_at = models.DateTimeField()
I store JSON data in wh_data.
[
{
"id":4124124,
"stocks":[
{
"wh":507,
"qty":2
},
{
"wh":2737,
"qty":1
}
],
},
{
"id":746457457,
"stocks":[
{
"wh":507,
"qty":3
}
]
}
]
Note: it's data for one row - 2022-06-06.
I need to calculate the sum inside stocks by grouping them by wh and by created_at so that the output is something like this
[
{
"wh":507,
"qty":5,
"created_at":"2022-06-06"
},
{
"wh":2737,
"qty":1,
"created_at":"2022-06-06"
},
{
"wh":507,
"qty":0,
"created_at":"2022-06-07"
},
{
"wh":2737,
"qty":2,
"created_at":"2022-06-07"
}
]
I know how to group by date, but I don't understand how to proceed with aggregations inside JsonField.
StocksHistory.objects.extra(select={'day': 'date( created_at )'})
.values('day')
.annotate(
???
)
A solution is suitable, both through Django ORM and through RAW SQL.

Answer 1

demo
WITH cte AS (
SELECT
jsonb_path_query(js, '$[*].stocks.wh')::numeric AS wh,
jsonb_path_query(js, '$[*].stocks.qty')::numeric AS b,
_date
FROM (
VALUES ('[
{
"id":4124124,
"stocks":[
{
"wh":507,
"qty":2
},
{
"wh":2737,
"qty":1
}
]
},
{
"id":746457457,
"stocks":[
{
"wh":507,
"qty":3
}
]
}
]'::jsonb)) v (js),
(
VALUES ('2022-06-06'), ('2022-06-07')) ss_ (_date)
),
cte2 AS (
SELECT
wh, sum(b) AS qty,
_date
FROM
cte
GROUP BY
1,
3
ORDER BY
1
)
SELECT
array_agg(row_to_json(cte2.*)::jsonb)
FROM
cte2;