ORDER BY Clause

As its name suggests, the ORDER BY clause orders the values or objects returned by the query.

If the ORDER BY clause contains multiple elements, the left-to-right sequence of the elements determines the high-to-low precedence.

The ASC keyword specifies ascending order (the default), and the DESC keyword indicates descending order.

When using the ORDER BY clause, the SELECT clause must return an orderable set of objects or values. You cannot order the values or objects for values or objects not returned by the SELECT clause. For example, the following query is valid because the ORDER BY clause uses the objects returned by the SELECT clause:

SELECT o
FROM Customer c JOIN c.orders o JOIN c.address a
WHERE a.state = ’CA’
ORDER BY o.quantity, o.totalcost

The following example is not valid because the ORDER BY clause uses a value not returned by the SELECT clause:

SELECT p.product_name
FROM Order o, IN(o.lineItems) l JOIN o.customer c
WHERE c.lastname = ’Faehmel’ AND c.firstname = ’Robert’
ORDER BY o.quantity