title: select all users where count() equals a specific value
body: <pre><code>   $sql = "SELECT * FROM cars WHERE COUNT(brand)='4'";
     $results = mysql_query($sql);
     $rows = mysql_fetch_array($results);
     print_r($rows);
  </code></pre>
  
  <p>the table cars has these columns: </p>
  
  <pre><code>id brand     price
  0  bmw
  1  corvette
  2  mercedes
  3  bmw
  4  bmw
  5  toyota
  6  bmw
  7  honda
  8  lotus
  </code></pre>
  
  <p>this is what I am trying to do, return from the table <code>'cars'</code> every brand that has 4 different cars. In this example bmw has 4
  4 different cars is 4 different rows with the same brand name.
  so I am trying to echo the name of the brand where the total number of inventory is 4. 
  I hope I made sense, any help would be appreciated. </p>
  
  <p>EDIT: I tried 
  SELECT * FROM cars LEFT JOIN users ON cars.user_id=users.user_id HAVING count(user_id) = 4   this is not working any ideas? </p>