你应该积极地不习惯抑制错误。错误是有原因的。相反，在您的代码中正确和防御地处理它们，并继续改进代码，直到错误消失。

您应该执行以下操作：

  $ conn = mysql_connect（$ host，$ user，$ pass）; 

 //总是测试看你的动作/连接/任何成功的
如果（！$ conn）{
 //发生错误。处理错误
 //显示用户的消息，向`error_log（）'写一条消息，任何适当的
} 
 else mysql_select_db（$ dbname）; 
 

在生产系统上，您不应显示错误，因为它可能会放弃您的代码的详细信息，数据库。相反，请在php.ini或运行时关闭 display_errors ：

  //在开发和生产中，确保报告所有错误
 error_reporting（E_ALL& E_STRICT）; 

 //在开发中显示屏幕上的所有错误，以便处理它们，因为它们发生
 ini_set（'display_errors'，1）; 

 //在生产中将它们关闭
 ini_set（'display_errors'，0）; 
 

事实上，使用 @ 在这个经典问题中，第二次被投票支持PHP的不良做法

Hey guys I was wondering why you would "suppress" a php error? I obviously see the difference in the extra line that spits out from the error... but is it good to suppress it?

 Access denied for user 'user'@'localhost' (using password: YES) 

Vs

Warning: mysql_connect() [function.mysql-connect]: Access denied for user 'user'@'localhost'       (using password: YES) in (deleted) on line 8
Access denied for user 'user'@'localhost' (using password: YES)

If so, should I get into the habit of typing @ at the start of my mysql queries in my php ?

Thanks!

You should positively NOT get into the habit of suppressing errors. The errors are there for a reason. Instead, handle them properly and defensively in your code, and keep refining your code until the errors are gone.

You should do things like:

$conn = mysql_connect($host, $user, $pass);

// Always test to see if your action/connection/whatever was successful
if (!$conn) {
  // something went wrong.  handle the error
  // Display a message for the user, write a message to `error_log()`, whatever's appropriate
}
else mysql_select_db($dbname);

On a production system, you should never display errors, since it risks giving up details of your code and database. Instead, turn display_errors off in php.ini, or at runtime:

// In development and production, make sure all errors are reported
error_reporting(E_ALL & E_STRICT);

// In development show all errors on screen so you handle them as they occur
ini_set('display_errors', 1);

// In production turn them off
ini_set('display_errors', 0);

In fact, error suppression with @ is the second most voted for PHP bad practice in this classic question.