title: Couldn't find driver when use pdo to connect to mssql in php
body: <p>I've downloaded and installed drivers in phpext. When I check phpinfo(), figure out drivers installed successfully. But when I use this code to check connection:</p>
  
  <pre><code>$dsn = 'mssql:host=localhost;dbname=chat';
  $user = 'sa';
  $password = '123';
  try {
      $dbh = new PDO($dsn, $user, $password);
  } catch (PDOException $e) {
      echo 'Connection failed: ' . $e-&gt;getMessage();
  }
  </code></pre>
  
  <p>This exception appears:</p>
  
  <blockquote>
    <p>Connection failed: could not find driver
    Could you please help me?</p>
  </blockquote>