Equivalence of from dual in PostgreSQL

Question

I work with Hibernate and Oracle. I used this code :

     if (null != sessionFactory) {                 Session s = currentSession.get();                      if ((null == s) || !s.isOpen()) {                     s = sessionFactory.openSession();                     currentSession.set(s);                 } else {                     try {                         HibernateWork hibernateWork = new HibernateWork("SELECT 1 FROM DUAL");                         s.doWork(hibernateWork);                     } catch (Exception e) {                                                 s = sessionFactory.openSession();                         currentSession.set(s);                     }                 }                      return s;             } 

I want to do the same thing with PostgreSQL, but PostgreSQL does NOT support the ‘FROM dual’ syntax. I want to know equivalence of dual in PostgreSQL.

Answer 1

You don't need a FROM clause at all. Just SELECT 1 will do it.