conditionProcess.js

import("system.logging");
import("system.result");
import("system.vars");

if(vars.exists("$param.OfferId_param") && vars.get("$param.OfferId_param") != "")
    result.string("OFFERITEM.OFFER_ID = ('" + vars.get("$param.OfferId_param") + "')");  
else
    result.string("");