HI!!
I need a formula for a running total field, I try something like the follow but doesn´t work. It may be sum only  by two true conditional if statements.
if {cuentas_ha_cobrar.marca_pagado}="SI" then
{cuentas_ha_cobrar.importe_cobrado_parcial}
else if({cuentas_ha_cobrar.marca_pagado})="NO" and {cuentas_ha_cobrar.diff}>0 and datediff("m",{cuentas_ha_cobrar.fecha_pago},{?mes_rendicion})=0 then
{cuentas_ha_cobrar.importe_cobrado_parcial}
else
0

I get the error message in the designer . It not possible undo this comnnad. Would you like perform this command  anyway ?.
Goodbye!! Sorry for my English