$query="select vehiculo,fecha_carga,rendimiento_kilometro,rendimiento_real,ticket,factura,costo_total,empresa
from carga_combustible
where factura ='$factura' and empresa='$empresa'
order by fecha_carga desc
union
select sum(costo_total) as monto from carga_combustible where factura ='$factura'";
$result=mysqli_query($con, $query) or die (mysqli_error());