如何在PHP中使用MySQL整数增量+1?

Currently when the user loads a PHP page I have a code that goes into the MySQL Table, and sets an INTeger +1 of itself. The problem is that randomly this number will reset itself to zero! Not sure why this happens.

$sql = "UPDATE `MyTable` SET My_INTEGER=My_INTEGER+1";

Why does the INTeger reset itself? How can I avoid that, or what is the best practice for updating an INTeger by +1 on a page load?