What is this operator <=> in MySQL?

I&#39;m working on code written by a previous developer and in a query it says, WHERE p.name &lt;=&gt; NULL What does `&lt;=&gt;` mean in this query? Is it something equal to `=`? Or is it a syntax error? But it is not showing any errors or exceptions. I already know that `&lt;&gt;` = `!=` in [MySQL][1]. [1]: http://en.wikipedia.org/wiki/MySQL