Format JSON Postgresql - json

Question

I'm using inner join to join 3 tables, Owner, Store and Machine.
I'm trying to view output JSON from multiple tables like this:
SELECT ow.*, st.*, ma.*
FROM owner ow
INNER JOIN st.store ON ow.OwnerId = st.OwnerId
INNER JOIN machine ma ON ma.StoreId = st.StoreId;
I want JSON formatted like this:
{
"OwnerId": "1d2dd",
"Name": "name test",
"Store":[{
"StoreId": "s3ss5",
"Name": "Store1",
"Code": "bla",
"Machine":[{
"MachineId": "axpeo",
"Name": "Machine1",
"Type": "type1"
}]
},
{
"StoreId": "ddf22",
"Name": "Store2",
"Code": "ble",
"Machine":[{
"MachineId": "weds",
"Name": "Machine2",
"Type": "type2"
},
{
"MachineId": "axdso",
"Name": "Machine3",
"Type": "type3"
}]
}]
}
but the return JSON is not formatted like this
I'm using PostgreSQL.

Answer 1

The easiest (and probably only sensible) way to do this is to build JSON sub-documents from individual records at table level and only then hierarchically joining them:
SELECT json_build_object('OwnerId', ownerid,
'Name', name,
'Store', stores)
FROM owner
JOIN (
SELECT ownerid,
json_agg(
json_build_object('StoreId', storeid,
'Name', name,
'Code', code,
'Machine', machines)) AS stores
FROM store
JOIN (
SELECT storeid,
json_agg(
json_build_object('MachineId', machineid,
'Name', name,
'Type', type)) AS machines
FROM machine
GROUP BY storeid) m USING (storeid)
GROUP BY ownerid) s USING (ownerid);

Answer 2

The output is not exactly what i want, but it is better...this is the output
[{
"OwnerId": "1d2dd",
"Name": "name test",
"Store":{
"StoreId": "s3ss5",
"Name": "Store1",
"Code": "bla",
"Machine":{
"MachineId": "axpeo",
"Name": "Machine1",
"Type": "type1"
}
}
},
{
"OwnerId": "1d2dd",
"Name": "name test",
"Store":{
"StoreId": "ddf22",
"Name": "Store2",
"Code": "ble",
"Machine":{
"MachineId": "weds",
"Name": "Machine2",
"Type": "type2"
}
}
},
{
"OwnerId": "1d2dd",
"Name": "name test",
"Store":{
"StoreId": "ddf22",
"Name": "Store2",
"Code": "ble",
"Machine":{
"MachineId": "axdso",
"Name": "Machine3",
"Type": "type3"
}
}
}]
it does not join the machines from the same store yet like an array

Answer 3

For one-to-many relationships formatted to JSON try something like this:
SELECT "owner"."id",
json_agg(DISTINCT "store".*) AS "stores",
json_agg(DISTINCT "machine".*) AS "machines"
FROM "owners"
INNER JOIN "stores"
ON "stores"."ownerId" = "owners"."id"
INNER JOIN "machines"
ON "machines"."storeId" = "stores"."id"
WHERE "owner" = 1
GROUP BY "owner"."id";