robbyrussell/oh-my-zsh — pull request #2441 by jiukunz (2014-01-17 15:46:16+00:00)
Title: Fix a bug.

In macOS, I install mysql using brew, and type mysql it will redirect to /var/empty.
See following issues:
http://stackoverflow.com/questions/10442449/cant-use-which-mysql-in-zsh-but-in-bash-work
http://stackoverflow.com/questions/7956345/osx-mysql-command-goes-in-var-empty