Código SQL [-]SELECT VTA.TREN ,SUM(VTA.NUM_PASAJEROS) + SUM(VJS.NUM_PASAJEROS) AS TOTAL_PASAJEROS FROM Ventas AS VTA INNER JOIN Viajes AS VJS ON VTA.TREN = VJS.TREN GROUP BY VTA.TREN
SELECT VTA.TREN ,SUM(VTA.NUM_PASAJEROS) + SUM(VJS.NUM_PASAJEROS) AS TOTAL_PASAJEROS FROM Ventas AS VTA INNER JOIN Viajes AS VJS ON VTA.TREN = VJS.TREN GROUP BY VTA.TREN