SELECT changes, stmt_date::date FROM pgmemento.table_event_log el
  JOIN pgmemento.row_log r ON (r.event_id=el.id)
  JOIN pgmemento.transaction_log t on (el.transaction_id=t.txid)
WHERE r.changes ?& (SELECT array_agg(key)
                    FROM pgmemento.row_log,
                    LATERAL jsonb_each_text(changes)
                    WHERE key like '%_stat'
                    GROUP BY key)
ORDER BY stmt_date::date

changes, stmt_date
{"X_stat": "INCOMING"}, 2017-12-13
{"W_stat": "CREATED"}, 2017-12-13