最近安装php7 忽然发现mysql用不了，临时解决了一下，php.ini里面配置了下mysqli.socket文件地址
http://php.net/manual/zh/book.mysqlnd.php
For those who manually compiled MySQL, the default
mysqlnd settings may results in error.
Your mysql_error() function may give you this message:
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No such file or directory (trying to connect via unix:///tmp/mysql.sock)
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This is because your manually compiled MySQL has its own place for socket.
You need to provide PHP a reference for an appropriate mysql socket.
That means you need to edit php.ini and add a section like this:
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[mysql]
mysql.default_socket=”/your/path/to/mysql.sock”
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https://stackoverflow.com/questions/1676688/php-mysql-connection-not-working-2002-no-such-file-or-directory