title: Trying to find differences of hours between two dates in MySQL
body: <p>I've been trying to learn some SQL but I'm rather struggling with the language. I'm trying to find the difference between two dates(departure and arrival) from a table. Other places have stated to use DATEDIFF, though I'm trying to pull the data directly from a table instead of keying in the dates manually. Here's my horrible attempt at trying to use this function</p>
  
  <pre><code>SELECT DATEDIFF(a.departure_time, a.arrival_time) as HourDiff;
  FROM airlines a
  WHERE HourDiff &gt;= 8
  </code></pre>
  
  <p>I'm also trying to find differences of time that exceeds over 8 hours but honestly I really don't know what I'm currently doing... What is the right way I should be writing this?</p>