title: SQL show difference between 2 tables
body: <p>I know there are similar questions, but I can't find solution to what I need to do.</p>
  
  <p>First of all I have 2 tables :</p>
  
  <ul>
  <li>SD.Airlines (16k+ rows)</li>
  <li>SD.AirlineRatings (405 rows)</li>
  </ul>
  
  <p>I need to find which records form SD.AirlineRatings do I have in SD.Airlines, I did this :</p>
  
  <pre><code>SELECT b.Name AS Airline FROM SD.Airlines b
  LEFT JOIN SD.AirlineRatings a ON a.AirlineName = b.Name
  WHERE a.AirlineName IS NOT NULL;
  </code></pre>
  
  <p>Works fine, showed me 249/405 records. Now... If I need to compare those 249 records towards SD.AirlineRatings and check which ones I don't have.</p>
  
  <p>I bet answer is simple but I don't know SQL that much.</p>
  
  <p>Thanks</p>