Magento – How to get all orders(and orders sum) for current customer

create a module which will add new tab in customer tab.

Step1: create Mydons_Customertab.xml at app/etc/modules/Mydons_Customertab.xml and code of this file:

    <?xml version="1.0"?><config>
        <modules>
            <Mydons_Customertab>
                <active>true</active>
                <codePool>local</codePool>
            </Mydons_Customertab>
        </modules>
    </config> 

Step2: create config.xml at app/code/local/Mydons/Customertab/etc/ and it code is

<?xml version="1.0" ?>
<config>
   <modules>
       <Mydons_Customertab>
           <version>0.1.0</version>
       </Mydons_Customertab>
   </modules>

     <adminhtml>
        <layout>
            <updates>
                <customertab>
                    <file>customertab.xml</file>
                </customertab>
            </updates>
        </layout>
        </adminhtml>
   <global>
       <blocks>
           <customertab>
               <class>Mydons_Customertab_Block</class>
           </customertab>
       </blocks>
 </global>
</config>

Step3: add tab code class file location:

app/code/local/Mydons/Customertab/Mydons/Customertab/Block_Adminhtml/Customer/Edit/Tab/Action.php

code is

<?php 

/**
 * Adminhtml customer action tab
 *
 */
class Mydons_Customertab_Block_Adminhtml_Customer_Edit_Tab_Action
 extends Mage_Adminhtml_Block_Template
    implements Mage_Adminhtml_Block_Widget_Tab_Interface
{

    public function __construct()
    {
        $this->setTemplate('customertab/action.phtml');

    }

    public function getCustomtabInfo(){

        $customer = Mage::registry('current_customer');
        $customtab='My Custom tab Action Contents Here';
        return $customtab;
        }

    /**
     * Return Tab label
     *
     * @return string
     */
    public function getTabLabel()
    {
        return $this->__('Action Center');
    }

    /**
     * Return Tab title
     *
     * @return string
     */
    public function getTabTitle()
    {
        return $this->__('Action Tab');
    }

    /**
     * Can show tab in tabs
     *
     * @return boolean
     */
    public function canShowTab()
    {
        $customer = Mage::registry('current_customer');
        return (bool)$customer->getId();
    }

    /**
     * Tab is hidden
     *
     * @return boolean
     */
    public function isHidden()
    {
        return false;
    }

     /**
     * Defines after which tab, this tab should be rendered
     *
     * @return string
     */
    public function getAfter()
    {
        return 'tags';
    }

}
?>

and then action.phtml at design\adminhtml\default\default\template\customertab\ code is

   <?php
$total=0;
echo $customer_email=Mage::registry('current_customer')->getEmail();
$collection = Mage::getModel('sales/order')
            ->getCollection()
          //  ->addFieldToFilter('status', 'complete')
            ->addAttributeToFilter('customer_email',array('like'=>$customer_email));
            foreach($collection as $eachOrder){
            echo $eachOrder->getGrandTotal();
            $total+=$eachOrder->getGrandTotal();
            echo $eachOrder->getId();
            echo "<br/>";
            }
            echo  $total;
    ?>

Step4: customertab.xml at app\design\adminhtml\default\default\layout\

code is

<?xml version="1.0"?>
<layout version="0.1.0">
    <adminhtml_customer_edit>
         <reference name="customer_edit_tabs">
            <action method="addTab"><name>customer_edit_tab_actionr</name><block>customertab/adminhtml_customer_edit_tab_action</block></action>
        </reference>
   </adminhtml_customer_edit>
</layout>