title: Laravel find missing row inside the table
body: <p>Let's say I have the following table called <code>TheSeriesEpisodes</code> made of composite key (seriesID, episodeNo):</p>
  
  <pre><code>seriesID | episodeNo | otherField
  ---------------------------------
  1         1           blabla
  1         4           blabla
  1         5           blabla
  1         6           blabla
  2         1           blabla
  2         2           blabla
  2         3           blabla
  2         5           blabla
  </code></pre>
  
  <p>As you can see there are 2 series (series 1 and series 2).
  Series 1 has episode 2 and 3 missing, Series 2 has episode 4 missing.</p>
  
  <p>How would I get a list of all missing episodes for a particular TV serial.</p>
  
  <p>I can not think about any method stopped here:</p>
  
  <pre><code>TheSeriesEpisodes::
  </code></pre>