title: Equivalence of from dual in PostgreSQL
body: <p>I work with Hibernate and Oracle. I used this code :</p>
  <pre><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(&quot;SELECT 1 FROM DUAL&quot;);
                          s.doWork(hibernateWork);
                      } catch (Exception e) {
                         
                          s = sessionFactory.openSession();
                          currentSession.set(s);
                      }
                  }
      
                  return s;
              }
  </code></pre>
  <p>I want to do the same thing with PostgreSQL, but PostgreSQL does NOT support the ‘FROM dual’ syntax. I want to know equivalence of  <strong>dual</strong> in PostgreSQL.</p>