title: PDO misbehaving with bind parameters
body: <p>I have simple SQL query that could benefit from bind variables so I have written like this:</p>
  
  <pre><code>$stmt = $this-&gt;db-&gt;prepare("SELECT * FROM activities WHERE user_id=':user_id' AND date(start_time)=date(':on_specific_day')");
  $stmt-&gt;bindParam(':user_id',$where['user_id']); 
  $stmt-&gt;bindParam(':on_specific_day',$where['on_specific_day']); 
  </code></pre>
  
  <p>As you can see there is an associative array called <code>where</code> which is used to store my where conditions. When I execute this statement it doesn't return any errors but the row count is zero. If I instead discard my dream of using bind variables and do this:</p>
  
  <pre><code>$stmt = $this-&gt;db-&gt;prepare("SELECT * FROM activities WHERE user_id='{$where['user_id']}' AND date(start_time)=date('{$where['on_specific_day']}')");
  </code></pre>
  
  <p>The query runs just fine and returns 2 results in my test case. Can someone help me from slipping into madness. :^)</p>