code to get the child node in product hierchery

static void queryForHierarchyNodes(Args _args)
{
    EcoResCategory          ecoResCategoryMobile, ecoResCategoryInfo, ecoResCategoryLast;
    QueryRun                qRun;
    QueryBuildDataSource    qDS;
    #EcoResCategoryDefaults

    select * from ecoResCategoryMobile where ecoResCategoryMobile.RecId == 5637170077 ;//5637163389;//5637163386; //5637163389;

    qRun        = new QueryRun(new Query());
    qDS = qRun.query().addDataSource(tableNum(ecoResCategory));

    qDS.addRange(fieldNum(EcoResCategory, CategoryHierarchy))
                    .value(queryValue(ecoResCategoryMobile.CategoryHierarchy));

    qDS.addRange(fieldNum(EcoResCategory, NestedSetLeft))
                    .value(Global::queryRange(ecoResCategoryMobile.NestedSetLeft, ecoResCategoryMobile.NestedSetRight));

    qDS.addRange(fieldNum(EcoResCategory, NestedSetRight))
                    .value(Global::queryRange(ecoResCategoryMobile.NestedSetLeft, ecoResCategoryMobile.NestedSetRight));

    while (qRun.next())
    {
        ecoResCategoryInfo  = qRun.get(tableNum(EcoResCategory));
        //select ecoResCategoryLast where ecoResCategoryLast.ParentCategory == ecoResCategoryInfo.RecId;
        //if(!ecoResCategoryLast)
        {
            //info(ecoResCategoryInfo.getLeafNodes().Name);
            info(ecoResCategoryInfo.Name);
        }
    }
}