mysql.sock 오류 해결

https://stackoverflow.com/questions/35026553/mysql-error-the-server-quit-without-updating-pid-file

https://serverfault.com/questions/459316/error-2002-mysql-socket-tmp-mysql-sock

https://stackoverflow.com/questions/9420701/mysqli-connect-not-working-on-mamp

http://faq.hostway.co.kr/Linux_DB/8085

https://ssumer.com/qa-%EB%A7%A5%EB%B6%81-mysql-%EA%B5%AC%EB%8F%99%EC%9D%B4-%EC%95%88%EB%90%98%EC%9A%94/