Postgres Jsonb aggregation - postgresql

Question

I am trying to achieve following (Result Required) output from POSTGRES jsonb columns, but not getting desired result using "jsonb_agg" function.
I went through this postgres document https://www.postgresql.org/docs/12/functions-json.html, but no luck here.
Also am not that good in json data in postgres, so please suggest good resource for json formatting related stuff for postgres.
City
JColA
JColB
NY
[{"id":"ID1","name":"ID1_NAME","type":"ID1_TYPE","amount":20.12,"full_name":null},{"id":"ID2","name":"ID2_NAME","type":"ID2_TYPE","amount":11.55,"full_name":null},{"id":"ID1","name":"ID1_NAME","type":"ID1_TYPE","amount":5.45,"full_name":null}]
[{"key":"key1","value":"1"},{"key":"key2","value":"2"},{"key":"key3","value":"3"}]
DC
[{"id":"ID1","name":"ID1_NAME","type":"ID1_TYPE","amount":1.5,"full_name":null},{"id":"ID3","name":"ID3_NAME","type":"ID3_TYPE","amount":1.2,"full_name":null},{"id":"ID4","name":"ID4_NAME","type":"ID4_TYPE","amount":1,"full_name":null}]
[{"key":"key1","value":"1"},{"key":"key1","value":"2"},{"key":"key1","value":"3"}]
DL
[{"id":"ID4","name":"ID4_NAME","type":"ID4_TYPE","amount":1.5,"full_name":null},{"id":"ID2","name":"ID2_NAME","type":"ID2_TYPE","amount":1.2,"full_name":null},{"id":"ID4","name":"ID4_NAME","type":"ID4_TYPE","amount":1,"full_name":null}]
[{"key":"key1","value":"2"},{"key":"key2","value":"2"},{"key":"key3","value":"4"}]
NY
[{"id":"ID1","name":"ID1_NAME","type":"ID1_TYPE","amount":4.5,"full_name":null},{"id":"ID2","name":"ID2_NAME","type":"ID2_TYPE","amount":2.2,"full_name":null},{"id":"ID4","name":"ID4_NAME","type":"ID4_TYPE","amount":6,"full_name":null}]
[{"key":"key4","value":"2"},{"key":"key2","value":"5"},{"key":"key2","value":"4"}]
DC
[{"id":"ID3","name":"ID3_NAME","type":"ID3_TYPE","amount":2.5,"full_name":null},{"id":"ID3","name":"ID3_NAME","type":"ID3_TYPE","amount":2.2,"full_name":null},{"id":"ID4","name":"ID4_NAME","type":"ID4_TYPE","amount":2,"full_name":null}]
[{"key":"key1","value":"2"},{"key":"key2","value":"2"},{"key":"key3","value":"4"}]
Required Result
City
AggJSonColA
AggJsonColB
NY
[{"id":"ID1","name":"ID1_NAME","type":"ID1_TYPE","amount":30.07,"full_name":null},{"id":"ID2","name":"ID2_NAME","type":"ID2_TYPE","amount":13.75,"full_name":null},{"id":"ID4","name":"ID4_NAME","type":"ID4_TYPE","amount":6,"full_name":null}]
[{"key":"key1","value":"1"},{"key":"key2","value":"11"},{"key":"key3","value":"3"}, {"key":"key4","value":"2"}]
DC
[{"id":"ID1","name":"ID1_NAME","type":"ID1_TYPE","amount":1.5,"full_name":null},{"id":"ID3","name":"ID3_NAME","type":"ID3_TYPE","amount":5.9,"full_name":null},{"id":"ID4","name":"ID4_NAME","type":"ID4_TYPE","amount":3,"full_name":null}]
[{"key":"key1","value":"8"},{"key":"key2","value":"2"},{"key":"key3","value":"4"}]
DL
[{"id":"ID4","name":"ID4_NAME","type":"ID4_TYPE","amount":1.5,"full_name":null},{"id":"ID2","name":"ID2_NAME","type":"ID2_TYPE","amount":1.2,"full_name":null},{"id":"ID4","name":"ID4_NAME","type":"ID4_TYPE","amount":1,"full_name":null}]
[{"key":"key1","value":"2"},{"key":"key2","value":"2"},{"key":"key3","value":"4"}]

Answer 1

You need to break out the arrays with jsonb_to_recordset, rebuild the objects using jsonb_build_object, and aggregate them back up with jsonb_agg
SELECT
A.City,
A.JColA,
B.JColB
FROM (
SELECT
City,
jsonb_agg(JColA) AS JColA
FROM (
SELECT
t.City,
json_build_object(
'id', id,
'name', name,
'type', type,
'amount', SUM(amount),
'full_name', full_name
) AS JColA
FROM YourTable t,
LATERAL jsonb_to_recordset(t.JColA)
AS arr(id varchar(10), name varchar(100), type varchar(100), amount decimal (18,2), full_name varchar(100))
GROUP BY
t.City, arr.id, arr.name, arr.type, arr.full_name
) A
GROUP BY
City
) A
JOIN (
SELECT
City,
jsonb_agg(JColB) AS JColB
FROM (
SELECT
t.City,
json_build_object(
'key', "key",
'value', SUM(value)
) AS JColB
FROM YourTable t,
LATERAL jsonb_to_recordset(t.JColB)
AS arr("key" varchar(10), value int)
GROUP BY
t.City, arr."key"
) B
GROUP BY
City
) B ON B.City = A.City;
I feel it's easier to requery the original table again, however if you want to avoid that, you could first aggregate all the arrays together by City, break them back out and re-aggregate.
SELECT
t.City,
(
SELECT
jsonb_agg(JColA)
FROM (
SELECT
json_build_object(
'id', id,
'name', name,
'type', type,
'amount', SUM(amount),
'full_name', full_name
) AS JColA
FROM jsonb_array_elements(t.JColA) AS outerArr,
LATERAL jsonb_to_recordset(outerArr)
AS arr(id varchar(10), name varchar(100), type varchar(100), amount decimal (18,2), full_name varchar(100))
GROUP BY
arr.id, arr.name, arr.type, arr.full_name
) A
) AS JColA,
(
SELECT
jsonb_agg(JColB)
FROM (
SELECT
json_build_object(
'key', "key",
'value', SUM(arr.value)
) AS JColB
FROM jsonb_array_elements(t.JColB) AS outerArr,
LATERAL jsonb_to_recordset(outerArr)
AS arr("key" varchar(10), value int)
GROUP BY
arr."key"
) B
) AS JColB
FROM (
SELECT
t.City,
jsonb_agg(JColA) AS JColA,
jsonb_agg(JColB) AS JColB
FROM YourTable t
GROUP BY
t.City
) t;
db<>fiddle