title: Oracle SQL Count and Avg in the same query
body: <p>I have the table PATIENT_SESSIONS with these fields:</p>
  <pre><code>PATIENT_ID,
  Session_Date,
  Session_Status (Scheduled, Completed, Canceled),
  PATIENT_Paid_Date,
  Amount
  </code></pre>
  <p>I want from this table to get for each patient_id the last session_date, the average between PATIENT_Paid_Date and Session_Date, the max(Amount) and count of Complete sessions in a single query.
  Is it possible?</p>