How do you do a limit query in HQL?

2018-12-31 17:56发布

In Hibernate 3, is there a way to do the equivalent of the following MySQL limit in HQL?

select * from a_table order by a_table_column desc limit 0, 20;

I don't want to use setMaxResults if possible. This definitely was possible in the older version of Hibernate/HQL, but it seems to have disappeared.

9条回答
回忆,回不去的记忆
2楼-- · 2018-12-31 18:36
Criteria criteria=curdSession.createCriteria(DTOCLASS.class).addOrder(Order.desc("feild_name"));
                criteria.setMaxResults(3);
                List<DTOCLASS> users = (List<DTOCLASS>) criteria.list();
for (DTOCLASS user : users) {
                System.out.println(user.getStart());
            }
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笑指拈花
3楼-- · 2018-12-31 18:38

This was posted on the Hibernate forum a few years back when asked about why this worked in Hibernate 2 but not in Hibernate 3:

Limit was never a supported clause in HQL. You are meant to use setMaxResults().

So if it worked in Hibernate 2, it seems that was by coincidence, rather than by design. I think this was because the Hibernate 2 HQL parser would replace the bits of the query that it recognised as HQL, and leave the rest as it was, so you could sneak in some native SQL. Hibernate 3, however, has a proper AST HQL Parser, and it's a lot less forgiving.

I think Query.setMaxResults() really is your only option.

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栀子花@的思念
4楼-- · 2018-12-31 18:41

If can manage a limit in this mode

public List<ExampleModel> listExampleModel() {
    return listExampleModel(null, null);
}

public List<ExampleModel> listExampleModel(Integer first, Integer count) {
    Query tmp = getSession().createQuery("from ExampleModel");

    if (first != null)
        tmp.setFirstResult(first);
    if (count != null)
        tmp.setMaxResults(count);

    return (List<ExampleModel>)tmp.list();
}

This is a really simple code to handle a limit or a list.

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