I know similar questions exist, such as MySQL with MAMP does not work with OSX Yosemite 10.10. However, I do have MAMP, nor XAMPP installed on my computer.
When I try to start mySQL from the PrefPane, nothing happens.
When I try to start mqSQL from the command line via
sudo /usr/local/mysql/support-files/mysql.server start
Starting MySQL . ERROR! The server quit without updating PID file
Solved by installing the latest mySQL release, following the instructions here http://coolestguidesontheplanet.com/get-apache-mysql-php-phpmyadmin-working-osx-10-10-yosemite/
As Yosemite gets more popular, more people are stumbling on this question. The answer above has to do with upgrading MySQL, so that it runs. The answer linked by @doc in the comments has to do with getting MySQL to start automatically. These are 2 separate issues.