title: MySql - HAVING vs WHERE
body: <p>What is the difference between these 2 queries?</p>
  
  <pre><code>SELECT f.name, 
         u.name, 
         u.id 
  FROM   families f 
         JOIN units u 
           ON f.unit_id = u.id 
  HAVING u.id IN( 43, 413, 22 )
  </code></pre>
  
  <p>And:</p>
  
  <pre><code>SELECT f.name, 
         u.name, 
         u.id 
  FROM   families f 
         JOIN units u 
           ON f.unit_id = u.id 
  WHERE  u.id IN( 43, 413, 22 )
  </code></pre>
  
  <p>The result of these 2 queries is exactly the same. So where is the difference?</p>