情况一：
$link = mysql_connect('localhost', 'root', '') or die('Can not connect to mysql server!');
mysql_select_db("test2", $link) or die(mysql_errno());情况二：
$link = mysql_connect('localhost', 'root', '') or die('Can not connect to mysql server!');
mysql_select_db("test2", $link) or die(mysql_errno() . mysql_error());情况一下无任何输出，情况二输出：“1049Unknown database 'test2'”。为什么情况一无法输出mysql错误的代码？求解……
$link = mysql_connect('localhost', 'root', '') or die('Can not connect to mysql server!');
mysql_select_db("test2", $link) or die(mysql_errno());情况二：
$link = mysql_connect('localhost', 'root', '') or die('Can not connect to mysql server!');
mysql_select_db("test2", $link) or die(mysql_errno() . mysql_error());情况一下无任何输出，情况二输出：“1049Unknown database 'test2'”。为什么情况一无法输出mysql错误的代码？求解……
If status is an integer , that value will be used as the exit status and not printed.