title: Magento make an (OR) using collections
body: <p>I've a custom module with custom table, now, i'm trying to make something like a filter for that table,  </p>
  
  <pre><code>Mage::getModel('comunity/news')-&gt;getCollection()
              -&gt;addFieldToFilter('title', array('like'=&gt;'%'.$this-&gt;getRequest()-&gt;getParam('q').'%'));
  </code></pre>
  
  <p>with this is enough, and works perfect, but i need to add another field, is simple if you do like this  </p>
  
  <pre><code>Mage::getModel('comunity/news')-&gt;getCollection()
              -&gt;addFieldToFilter('title', array('like'=&gt;'%'.$this-&gt;getRequest()-&gt;getParam('q').'%'))  
             -&gt;addFieldToFilter('shortdesc', array('like'=&gt;'%'.$this-&gt;getRequest()-&gt;getParam('q').'%'));
  </code></pre>
  
  <p>it works to, but it make an (AND) and i want an (OR), i was lookin into Varien_Data_Collection_Db class, the function addFieldToFilter make a call to _getConditionSql where you can see something like this </p>
  
  <pre><code>        if (is_array($fieldName)) {
          foreach ($fieldName as $f) {
              $orSql = array();
              foreach ($condition as $orCondition) {
                  $orSql[] = '('.$this-&gt;_getConditionSql($f[0], $f[1]).')';
              }
              $sql = '('. join(' or ', $orSql) .')';
          }
          return $sql;
      }
  </code></pre>
  
  <p>here an (OR) can be done, i've tried with  </p>
  
  <pre><code>-&gt;addFieldToFilter(array (
                  array('field'=&gt;'title', 'like'=&gt;'%'.$this-&gt;getRequest()-&gt;getParam('q').'%'),
                  array('field'=&gt;'shortdesc', 'like'=&gt;'%'.$this-&gt;getRequest()-&gt;getParam('q').'%'),
              ))
  </code></pre>
  
  <p>but the query it makes is  </p>
  
  <pre><code>SELECT `main_table`.* FROM `uhma_comunidad_articulos` AS `main_table` WHERE (())
  </code></pre>
  
  <p>i need some help here
  thanks</p>