什么鬼，为什么不一样，mysql.so error！

xray@Ubuntu:~$ cat /etc/php5/conf.d/mysql.ini
cat: /etc/php5/conf.d/mysql.ini: No such file or directory
xray@Ubuntu:~$ sudo apt-get install php5-mysql
Reading package lists... Done
Building dependency tree       
Reading state information... Done
php5-mysql is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 282 not upgraded.
xray@Ubuntu:~$ cat /etc/php5/conf.d/mysql.ini
cat: /etc/php5/conf.d/mysql.ini: No such file or directory

xray@Ubuntu:~$