Mac下mysql安裝完成后，并沒有卸載文件，只能自己卸載
首先需要停止mysql的有關進程
然后逐一執行代碼，徹底刪除mysql
sudo rm /usr/local/mysql
sudo rm -rf /usr/local/mysql*
sudo rm -rf /Library/StartupItems/MySQLCOM
sudo rm -rf /Library/PreferencePanes/My*
vim /etc/hostconfig (and removed the line MYSQLCOM=-YES-)
rm -rf ~/Library/PreferencePanes/My*
sudo rm -rf /Library/Receipts/mysql*
sudo rm -rf /Library/Receipts/MySQL*
sudo rm -rf /var/db/receipts/com.mysql.*
最后三句必須執行！
