[lev]

вот джобик для ясности (возможно будет понятней):

Query                   query = new Query();
    QueryBuildDataSource    qbds1, qbds2, qbds3;
    ;

    qbds1 = query.addDataSource(tableNum(SalesTable));
    qbds1.fetchMode(QueryFetchMode::One2One);
    qbds2 = qbds1.addDataSource(tableNum(CustTable));
    qbds2.fetchMode(QueryFetchMode::One2One);
    qbds3 = qbds2.addDataSource(tableNum(SalesLine));
    qbds3.fetchMode(QueryFetchMode::One2One);

    qbds1.addRange(fieldNum(SalesTable, SalesId)).value(SysQuery::valueNotEmptyString());
    qbds2.addRange(fieldNum(CustTable, AccountNum)).value(QueryValue('Тест'));
    qbds3.addRange(fieldNum(SalesLine, ItemId)).value(QueryValue('Товар'));

    info(qbds1.toString());