How do i convert each row from resultset to a json and then add them to a single array in postgresql

I have three tables

Owner
-----------------------
id         | long
name       | string

Animal
-----------------------
id         | long
status     | string
external_d | string
region     | long (fk to region table)
owner_id    | long (fk to owner table)

Region
-----------------------
id         | long
name       | string

I want to get multiple rows from the Animal table. Each record should contain the id, status, externalId and region.

Each row should be a JSON object and all the results should be in an array. e.g

[
   {id: 3, status: 'alive', externalId: 'abc90', regionId: 2},
   {id: 9, status: 'dead', externalId: 'xuy12', regionId: 2},
   {id: 13, status: 'alive', externalId: 'ter34', regionId: 2}
]

I have tried to make the query as follows.

SELECT JSON_ARRAY(
    JSON_OBJECT(
        'id', id, 
        'externalId', externalId, 
        'status', status, 
        'regionId', regionId
        )
    ) as final_data
    FROM 
    (SELECT 
        a.id as id, 
        a.external_id as externalId, 
        a.status as status, 
        a.region_id as regionId 
    FROM 
        myDB.animal a 
    WHERE a.owner_id=12) as data;

running the above query gives me all the required columns in JSON format but each row is an array instead of all JSON objects in a single array.

Can someone help me solve this.

>Solution :

You can use json_arrayagg() to return all JSON objects in a single array :

SELECT JSON_ARRAYAGG(
          JSON_OBJECT(
            'id', id, 
            'externalId', external_id, 
            'status', status, 
            'regionId', region_id
          )
       ) as final_data
FROM animal
WHERE owner_id=12;

Demo here