title: How to add customer email to order grid in magento 1.6
body: <p>i am using magento 1.6
  and want to add cutomer email,coupon code and shipping detials to sales order grid</p>
  
  <p>can you guys please tell me how to do that</p>
  
  <p>it tried using this</p>
  
  <pre><code>copy
  app/code/core/Mage/Adminhtml/Block/Sales/Order/Grid.php
  to
  app/code/local/Mage/Adminhtml/Block/Sales/Order/Grid.php
  
  then under the following line
  
  $collection = Mage::getResourceModel($this-&gt;_getCollectionClass());
  
  add
  
  $collection-&gt;getSelect()-&gt;joinLeft(array('sfo'=&gt;'sales_flat_order'),'sfo.entity_id=main_table.entity_id',array('sfo.customer_email'));
  
  then in the _prepareColumns() method add
  
      $this-&gt;addColumn('customer_email', array(
          'header' =&gt; Mage::helper('sales')-&gt;__('Customer Email'),
          'index' =&gt; 'customer_email',
          'filter_index' =&gt; 'sfo.customer_email',
      ));
  note. you will need to add a 'filter_index' to all calls to addColumn pointing to main_table.field_name
  </code></pre>
  
  <p>but its not working </p>