Install MySQL on OS X El Capitan
However, at the time of writing the script is not compatible with OS X El Capitan (10.11)
Install MySQL using Homebrew
An alternative to the aforementioned installation script is installing MySQL using Homebrew. This gist assumes you already have Homebrew installed, if not first read the article "Homebrew and El Capitan"
Make sure Homebrew has the latest formulae, so run
brew update first