private String getOrderByString() {
StringBuffer orderBuffer = new StringBuffer("");
if (orderBys != null && !orderBys.isEmpty()) {
orderBuffer.append(" ORDER BY ");
OrderBy lastOrderBy = orderBys.get(orderBys.size() - 1);
for (OrderBy orderBy : orderBys) {
orderBuffer.append(Util.escapeSQL(orderBy.getColumn()));
if (orderBy.isAscending()) {
orderBuffer.append(" ASC");
} else {