title: filter the product collection with an Array in Magento
body: <p>I've got this problem that I can't solve. Partly because I can't explain it with the right terms. I'm new to this so sorry for this clumsy question.</p>
  
  <p>Below you can see an overview of my goal.</p>
  
  <p>I'm using Magento CE 1.7.0.2</p>
  
  <p>I have an Array with the name of <code>$params</code> in this i have some Category Ids...</p>
  
  <pre><code>$_productCollection = Mage::getResourceModel('reports/product_collection')-&gt;addAttributeToSelect('*');
  </code></pre>
  
  <p>Here <code>$_productCollection</code> is my custom product collection...</p>
  
  <p>How do i filter the product with <code>addFieldToFilter()</code> function by category</p>
  
  <p>I tried like <code>$_productCollection-&gt;addFieldToFilter('category',array('eq' =&gt; $params));</code></p>
  
  <p>But it is not working...</p>
  
  <p>Any ideas...</p>