title: [zend][db] fetchAll with multiple variables
body: <p>I'm trying to use fetchAll on a query that has 2 variables. I can't figure out the syntax.
  I can manage with only 1 variable:</p>
  
  <pre><code>$sql = "SELECT * FROM mytable WHERE field1 = ?";
  $this-&gt;_db-&gt;fetchAll($sql,$value1);  # that works
  </code></pre>
  
  <p>However I'm having some issues when query has multiple variables</p>
  
  <pre><code>$sql = "SELECT * FROM mytable WHERE field1 = ? AND field2 = ?";
  $this-&gt;_db-&gt;fetchAll($sql,$value1,$value2); # doesn't work
  $this-&gt;_db-&gt;fetchAll($sql,array("field1"=&gt;$value1,"field2"=&gt;$value2)); # doesn't work either
  </code></pre>
  
  <p>The reason why I want to use ? instead of placing the variables directly into the query is that I've learned that using ? allows for the query to be compiled generically by the db engine and improves performances.</p>