JPQL

[Deepika Joshi]

1. Select o
2. From Order o
3. Where o.qty>50
4. ORDER BY o.item

I thought removing removing line 4. would make it valid query, my logic is o.item is not part of select statement (first line).

Is it correct?


Thanks.

[Ralph Jaus]

I think the query expression is valid as it is ('select o' contains each state field and single value assocation field since it is resolved by the persistence provider like 'select o.name, o.item, o.price, ... from order o ...').

[Deepika Joshi]

To use GROUP BY we need to mention field name in Select clause,
don't we need to follow same rule for ORDER BY.

Am I correct?

Thanks.

[Ralph Jaus]

From JPA spec 4.9 (order by):

When the ORDER BY clause is used in a query, each element of the SELECT clause of the query must be one of the following:
1. an identification variable x
2. a single_valued_path_expression
3. a state_field_path_expression

So you can use identifaction variables without causing problems (see also the ORDER BY examples in the quoted JPA reference).