Add Order Count in Customer Grid

config.xml=========
<?xml version="1.0"?>
<config>
    <modules>
        <Quafzi_CustomerGridOrderCount>
            <version>0.2.4</version>
        </Quafzi_CustomerGridOrderCount>
    </modules>
    <global>
        <models>
            <quafzi_customergridordercount>
                <class>Quafzi_CustomerGridOrderCount_Model</class>
            </quafzi_customergridordercount>
        </models>
    </global>
    <adminhtml>
        <translate>
            <modules>
                <Quafzi_CustomerGridOrderCount>
                    <files>
                        <default>Quafzi_CustomerGridOrderCount.csv</default>
                    </files>
                </Quafzi_CustomerGridOrderCount>
            </modules>
        </translate>
        <events>
            <core_layout_block_create_after>
                <observers>
                    <quafzi_customergridordercount_adminhtml_block_html_before>
                        <class>quafzi_customergridordercount/observer</class>
                        <method>beforeBlockToHtml</method>
                    </quafzi_customergridordercount_adminhtml_block_html_before>
                </observers>
            </core_layout_block_create_after>
            <eav_collection_abstract_load_before>
                <observers>
                    <quafzi_customergridordercount_change_collection>
                        <class>quafzi_customergridordercount/observer</class>
                        <method>beforeCustomerCollectionLoad</method>
                    </quafzi_customergridordercount_change_collection>
                </observers>
            </eav_collection_abstract_load_before>
        </events>
    </adminhtml>
</config>
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Observer.php=======
<?php
/**
 * @package    Quafzi_CustomerGridOrderCount
 * @copyright  Copyright (c) 2013 Thomas Birke
 * @author     Thomas Birke <tbirke@netextreme.de>
 * @license    http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */

class Quafzi_CustomerGridOrderCount_Model_Observer
{
    public function beforeBlockToHtml(Varien_Event_Observer $observer) {
        $block = $observer->getEvent()->getBlock();
        if ($block instanceof Mage_Adminhtml_Block_Customer_Grid) {
            $this->_modifyCustomerGrid($block);
        }
    }

    protected function _modifyCustomerGrid(Mage_Adminhtml_Block_Customer_Grid $grid)
    {
        $this->_addOrderCountColumn($grid);

        // reinitialisiert die Spaltensortierung
        $grid->sortColumnsByOrder();
        // reinitialisiert die Sortierung und Filter der Collection
        $this->_callProtectedMethod($grid, '_prepareCollection');
    }

    /**
     * dirty hack...
     * @see http://www.webguys.de/magento/turchen-23-pimp-my-produktgrid/
     */
    protected function _callProtectedMethod($object, $methodName)
    {
        $reflection = new ReflectionClass($object);
        $method = $reflection->getMethod($methodName);
        $method->setAccessible(true);
        return $method->invoke($object);
    }

    protected function _addOrderCountColumn($grid)
    {
        $grid->addColumnAfter('order_count', array(
            'header'    => Mage::helper('customer')->__('Order Count'),
            'align'     => 'center',
            'width'     => '80px',
            'type'      => 'number',
            'filter'    => false,
            'index'     => 'order_count'
        ), 'customer_since');
    }

    public function beforeCustomerCollectionLoad(Varien_Event_Observer $observer)
    {
        $collection = $observer->getEvent()->getCollection();
        if ($collection instanceof Mage_Customer_Model_Resource_Customer_Collection) {
            $relationAlias = 'orders_to_count';

            $from = $collection->getSelect()->getPart(Zend_Db_Select::FROM);
            if (false === array_key_exists($relationAlias, $from)) {
                // not yet joined
                $orderTableName = Mage::getSingleton('core/resource')
                    ->getTableName('sales/order');

                $collection
                    ->getSelect()
                    ->joinLeft(
                        array($relationAlias => $orderTableName),
                        $relationAlias . '.customer_id=e.entity_id',
                        array('order_count' => 'COUNT(' . $relationAlias . '.customer_id)')
                    );
                $collection->groupByAttribute('entity_id');
            }
        }
    }
}

Add Customer Order Count in Order Grid

$collection->join(‘order’, ‘main_table.entity_id = order.entity_id’, ‘customer_email’);
$alias = ‘subselect’;
$subselect = Mage::getModel(‘Varien_Db_Select’,
Mage::getSingleton(‘core/resource’)->getConnection(‘core_read’)
)->from(‘sales_flat_order’, array(
‘customer_email as s_customer_email’,
‘count(*) as total_orders’)
)->group(‘customer_email’);

$collection->getSelect()
->joinInner(array($alias => $subselect),
“{$alias}.s_customer_email = order.customer_email”);

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$this->addColumn(‘total_revenue’, array(
‘header’ => Mage::helper(‘sales’)->__(‘Total Revenue’),
‘index’ => ‘total_revenue’,
‘filter_index’ => ‘ctotals.total_revenue’,
));

$this->addColumn(‘total_orders’, array(
‘header’ => Mage::helper(‘sales’)->__(‘Total Orders’),
‘index’ => ‘total_orders’,
‘filter_index’ => ‘ctotals.total_orders’,
));

Add Customer Email in Order Grid

$collection->join(‘order’, ‘main_table.entity_id = order.entity_id’, ‘customer_email’);
_____________________________________________________________________________________
$this->addColumn(‘customer_email’, array(
‘header’ => Mage::helper(‘sales’)->__(‘Customer Email’),
‘index’ => ‘customer_email’,
));