title: reproduce select distinct with get_db_data
body: <p>I am using for the first time MediaWiki so I apologize if this is a trivial question.
  I am retrieving data from an external database using </p>
  
  <pre><code>{{#get_db_data:
  db=mydb
  |from=tabledata
  |data=ts=ts,obs=observer,des=description
  }}
  </code></pre>
  
  <p>How can I obtain with this parser the same effect of the sql command <code>SELECT DISTINCT</code> ?</p>
  
  <p>Thank you.</p>