title: SQL: how to group by dates in a row?
body: <p>It might be already answered before, but apparently I am not googling it right.</p>
  
  <p>Let's say I have a table:</p>
  
  <pre><code>RecordingDate
  2018-07-01
  2018-07-02
  2018-07-06
  2018-07-09
  2018-07-10
  2018-07-11
  2018-07-12
  2018-07-16
  2018-07-17
  2018-07-18
  </code></pre>
  
  <p>I want to group the data by the date of the first recording and count days in a row with recordings:</p>
  
  <pre><code>DateOfFirstRecording  RecordingsInARow
  2018-07-01            2
  2018-07-06            1
  2018-07-09            4
  2018-07-16            3
  </code></pre>
  
  <p>How do I do that ?</p>