title: error with query REPLACE using mysql PDO
body: <p>I try to execute the following mysql query with pdo</p>
  
  <pre><code>REPLACE INTO session SET id = :id, user_id = :user_id, data = :data, timestamp = :timestamp
  </code></pre>
  
  <p>and I get the following error:</p>
  
  <pre><code>[18-Sep-2014 11:48:10] Exception Message: Unhandled Exception.
  SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?, data = ?, timestamp = ?' at line 1.
  </code></pre>
  
  <p>You can find the error back in the log.:</p>
  
  <pre><code>Query:REPLACE INTO session SET id = :id, user_id = :user_id, data = :data, timestamp = :timestamp
  </code></pre>
  
  <p>Params:</p>
  
  <pre><code>Array
  (
      [id] =&gt; sv9o264ciicsfd8porp1v0gl46
      [user_id] =&gt; 0
      [data] =&gt; version|s:8:"computer";linkedin|a:1:{s:5:"state";s:7:"Q7HXzKo";}github|a:1:{s:5:"state";s:7:"Q7HXzKo";}
      [timestamp] =&gt; 1411030090
  )
  </code></pre>
  
  <p>My Table session structure is:</p>
  
  <pre><code>CREATE TABLE IF NOT EXISTS `session` (
    `id` varchar(255) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
    `user_id` mediumint(10) NOT NULL,
    `data` text COLLATE utf8_unicode_ci NOT NULL,
    `timestamp` int(40) NOT NULL DEFAULT '0',
    PRIMARY KEY (`id`),
    UNIQUE KEY `session` (`id`),
    UNIQUE KEY `id` (`id`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
  </code></pre>
  
  <p>When I use phpmyadmin to execute it is working fine.<br>
  Can you help me to understand what is the problem?</p>