title: COUNT(id) vs. COUNT(*) in MySQL
body: <p>Is there a difference between the following queries, assuming there is a primary field 'id' in the table (as in speed, etc)?</p>
  
  <pre><code>SELECT COUNT(id) 
    FROM table
  </code></pre>
  
  <p>vs. </p>
  
  <pre><code>SELECT COUNT(*) 
    FROM table
  </code></pre>