gistfile1.sql

SELECT
    "transaction".id, "transaction".amount,
    "transaction".currency, current_status.status
FROM "transaction" JOIN (
    SELECT                                                                                   
        transaction_id, MAX(id) AS max_id
    FROM transaction_history
    GROUP BY transaction_id) max_ids JOIN (
    SELECT
        id, transaction_id, status
    FROM
        transaction_history) current_status
WHERE
    "transaction".id = max_ids.transaction_id
    AND "transaction".id = current_status.transaction_id
    AND max_ids.max_id = current_status.id
    AND current_status.status = 'processing';