Using PHP and SQL on Desktop

Hello Everyone, I am rather new with Unity and would greatly appreciate any help you can give me. I want to make a multi-player game with user accounts using PHP and SQL to handle those accounts. Is this possible on PCs or Macs. All examples I have found use the web player. If so, are there any limitations? If not, what would be the best workaround for user accounts synced between computers on desktop games? Thank you.