SELECT
    planname,
    '{"c":"baz"}'::JSON,
    json_build_object(planname,1,'bar',2)
FROM bplaene
LIMIT 10
;

-- Complex nested JSON with arrays
SELECT json_build_object(
               'trans_id', t.trans_id,
               'user_data', json_build_object(
                       'user_id', t.user_id,
                       'user_username', t.user_username,
                       'user_full_name', t.user_full_name,
                       'user_street', t.user_street,
                       'user_postal_code', t.user_postal_code,
                       'user_additional_info', t.user_additional_info,
                       'user_country', t.user_country,
                       'user_vat_number', t.user_vat_number),
               'order_data', json_build_object(
                       'order_date', t.order_date,
                       'order_sum', t.order_sum,
                       'order_vat', t.order_vat,
                       'order_invoice_nr', t.order_invoice_nr
                   ),
               'locations',
               (SELECT json_agg(row_to_json(locations))
                FROM (SELECT l.address,
                             l.project_title,
                             (SELECT json_agg(row_to_json(f))
                              FROM (SELECT layername,
                                           data
                                    FROM sales.features) f) features

                      FROM sales.locations l) locations)
           ) transaction
FROM sales.transactions t