title: Understanding some MySQL Optimization tips
body: <p>Hey, I was looking up some ways to make my MySQL queries more optimized, I bought some into practice but for some I wish to understand why they are recommended.</p>
  
  <p>For example not using "LIMIT 10000,10" as I learned that MySQL reads 10010 rows, throws away the 10000 and returns the 10.</p>
  
  <p>Now what I want to know is:</p>
  
  <p>Referring to this article: <a href="http://forge.mysql.com/wiki/Top10SQLPerformanceTips" rel="nofollow">http://forge.mysql.com/wiki/Top10SQLPerformanceTips</a></p>
  
  <p>"Use a clever key and ORDER BY instead of MAX"</p>
  
  <ol>
  <li><p>What is a "clever key" ?</p></li>
  <li><p>What execution path does MySQL take to calculate MAX that it has been recommended to avoid it.</p></li>
  </ol>
  
  <p>Thank you.</p>