Consulta complicada

[hvaldez]

select clientes.id_cli, sum(ingresos.ingresos) as ingreso,
sum(compras.compras) as compra
from clientes left join ingresos on clientes.id_cli = ingresos.id_cli left join compras on clientes.id_cli = compras.id_cli
where ingresos.iva <> '0'
group by clientes.id_cli