title: Delete duplicates but keep 1 with multiple column key
body: <p>I have the following SQL select. How can I convert it to a delete statement so it keeps 1 of the rows but deletes the duplicate? </p>
  
  <pre><code>select s.ForsNr, t.* 
  from [testDeleteDublicates] s
  join (
      select ForsNr, period,  count(*) as qty
      from [testDeleteDublicates]
      group by ForsNr, period 
      having count(*) &gt; 1
  ) t on s.ForsNr = t.ForsNr and s.Period = t.Period
  </code></pre>