title: SQL distinct with group by in Oracle
body: <p>I have following SQL:</p>
  
  <pre><code>select 
    origin,destination,to_char(to_date(substr(ship_date,1,6),'YYMMDD'),
    'YYYY-MM-DD'),ship_date,trip_number, distinct ship_number  
  from shipment a 
  where 
    a.scc_code in ('xxxxx','xxxxx','xxxxx') 
    and load_status = 'S' and ship_date like '11%' 
    and shipper_id = XXXXXX
  group by origin,destination,ship_date,trip_number, ship_number
  </code></pre>
  
  <p>When I run this SQL in Oracle it gives ORA-00936: missing expression.  If I remove the distinct keyword, it runs fine.  Can anybody tell me the difference between those two things?</p>