如何使用Hibernate从Mysql获取最后一条记录？

Question

List<Lahetys> last = session.createQuery("from lahetys order by lahetysNro DESC LIMIT 1").list();

and in the log I got:

INFO: Hibernate: select  from order by  lahetysNro DESC LIMIT 1
WARN: SQL Error: 1064, SQLState: 42000
ERROR: You have an error in your SQL syntax; check the manual that corresponds to your       MySQL server version for the right syntax to use near 'from order by  lahetysNro DESC LIMIT 1' at line 1

What has happend to "from LAHETYS"? What is the best practice to handle that with HQL or/and with SQL?

Another problem:

Lahetys last = (Lahetys)session.createSQLQuery("select * from lahetys order by lahetysNro DESC LIMIT 1").uniqueResult();
session.getTransaction().commit();  

and I get a exception:

Ljava.lang.Object; cannot be cast to Lahetys 

So I can't cast an object to my Lahetys-object, weird?

Thank you! Sami

Answer 1

Your HQL query is invalid. LIMIT is not a valid HQL clause. To do that in Hibernate, just do

Query query = session.createQuery("from lahetys order by lahetysNro DESC");
query.setMaxResults(1);
Lahetys last = (Lahetys) query.uniqueResult();

Answer 2

When you're using HQL, you should specify fully qualified className instead of tableName. The same way you should specify propertyName instead of columnName. Also keep in mind that both are case - sensitive.

Looking at your queries & the exception you're getting, I'm assuming that lahetys is your table name & lahetysNro is your column name.

You should use for example: If your Lahetys class is located at com folder:

List<Lahetys> last = session.createQuery("from com.Lahetys order by lahetysNro DESC LIMIT 1").list();

For your 2nd question:

Here you have used SQL instead of HQL. When you use SQL with hibernate in such a way, it always returns List<Object[]> & not List<Lahetys[]> .