valueProcess.js

import("system.question");
import("system.vars");
import("Sql_lib");
import("system.result");

var contactId = vars.get("$field.CONTACT_ID");
var alreadyUsedMediums = new SqlBuilder().select("MEDIUM").from("COMMRESTRICTION").where("COMMRESTRICTION.CONTACT_ID", contactId);

result.string(alreadyUsedMediums);