This is a duplicate of the question Add Column to a grid (observer) - Column ‘store_id’ in where clause is ambiguous issue, here I explained how to add a column to the sales/order grid the right way (without file copy or a rewrite).
The sales/order grid uses the table sales_flat_order_grid to display its information, this is done to list all orders without adding joins and speeding-up the loading. In order to add a column to the grid you would need to add a field to this table and update the information in that field when an order is created/updated. Below the steps needed to add this to the grid:
I called the extension Example_SalesGrid, but you can change it to your own needs.
Let's start by creating the module init xml in /app/etc/modules/Example_SalesGrid.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!--
Module bootstrap file
-->
<config>
<modules>
<Example_SalesGrid>
<active>true</active>
<codePool>community</codePool>
<depends>
<Mage_Sales />
</depends>
</Example_SalesGrid>
</modules>
</config>
Next we create our module config xml in /app/code/community/Example/SalesGrid/etc/config.xml:
<?xml version="1.0" encoding="UTF-8"?>
<config>
<modules>
<Example_SalesGrid>
<version>0.1.0</version> <!-- define version for sql upgrade -->
</Example_SalesGrid>
</modules>
<global>
<models>
<example_salesgrid>
<class>Example_SalesGrid_Model</class>
</example_salesgrid>
</models>
<blocks>
<example_salesgrid>
<class>Example_SalesGrid_Block</class>
</example_salesgrid>
</blocks>
<events>
<!-- Add observer configuration -->
<sales_order_resource_init_virtual_grid_columns>
<observers>
<example_salesgrid>
<model>example_salesgrid/observer</model>
<method>addColumnToResource</method>
</example_salesgrid>
</observers>
</sales_order_resource_init_virtual_grid_columns>
</events>
<resources>
<!-- initialize sql upgrade setup -->
<example_salesgrid_setup>
<setup>
<module>Example_SalesGrid</module>
<class>Mage_Sales_Model_Mysql4_Setup</class>
</setup>
</example_salesgrid_setup>
</resources>
</global>
<adminhtml>
<layout>
<!-- layout upgrade configuration -->
<updates>
<example_salesgrid>
<file>example/salesgrid.xml</file>
</example_salesgrid>
</updates>
</layout>
</adminhtml>
</config>
Now we create the sql upgrade script in /app/code/community/Example/SalesGrid/sql/example_salesgrid_setup/install-0.1.0.php:
<?php
/**
* Setup scripts, add new column and fulfills
* its values to existing rows
*
*/
$this->startSetup();
// Add column to grid table
$this->getConnection()->addColumn(
$this->getTable('sales/order_grid'),
'customer_city',
'varchar(255) DEFAULT NULL'
);
// Add key to table for this field,
// it will improve the speed of searching & sorting by the field
$this->getConnection()->addKey(
$this->getTable('sales/order_grid'),
'customer_city',
'customer_city'
);
// Now you need to fullfill existing rows with data from address table
$select = $this->getConnection()->select();
$select->join(
array('address'=>$this->getTable('sales/order_address')),
$this->getConnection()->quoteInto(
'address.parent_id = order_grid.entity_id AND address.address_type = ?',
Mage_Sales_Model_Quote_Address::TYPE_BILLING
),
array('customer_city' => 'city')
);
$this->getConnection()->query(
$select->crossUpdateFromSelect(
array('order_grid' => $this->getTable('sales/order_grid'))
)
);
$this->endSetup();
Next we create the layout update file in /app/design/adminhtml/default/default/layout/example/salesgrid.xml:
<?xml version="1.0"?>
<layout>
<!-- main layout definition that adds the column -->
<add_order_grid_column_handle>
<reference name="sales_order.grid">
<action method="addColumnAfter">
<columnId>customer_city</columnId>
<arguments module="sales" translate="header">
<header>Customer City</header>
<index>customer_city</index>
<type>text</type>
<width>200</width>
</arguments>
<after>shipping_name</after>
</action>
</reference>
</add_order_grid_column_handle>
<!-- order grid action -->
<adminhtml_sales_order_grid>
<!-- apply the layout handle defined above -->
<update handle="add_order_grid_column_handle" />
</adminhtml_sales_order_grid>
<!-- order grid view action -->
<adminhtml_sales_order_index>
<!-- apply the layout handle defined above -->
<update handle="add_order_grid_column_handle" />
</adminhtml_sales_order_index>
</layout>
The last file needed is needed to update the data from a table other than sales/order (sales_flat_order). All fields in sales/order_grid matching the column name from sales/order is automatically updated in the sales/order_grid table.
/app/code/community/Example/SalesGrid/Model/Observer.php:
<?php
/**
* Event observer model
*
*
*/
class Example_SalesGrid_Model_Observer {
public function addColumnToResource(Varien_Event_Observer $observer) {
// Only needed if you use a table other than sales/order (sales_flat_order)
$resource = $observer->getEvent()->getResource();
$resource->addVirtualGridColumn(
'customer_city',
'sales/order_address',
array('billing_address_id' => 'entity_id'),
'city'
);
}
}
This code is based on the example from http://www.ecomdev.org/2010/07/27/adding-order-attribute-to-orders-grid-in-magento-1-4-1.html
Hope the example above solves your problem.
Error in column code use below code.
$this->addColumn('sales_rep', array(
'header' => Mage::helper('sales')->__('Sales Rep'),
'index' => 'sales_rep',
'type' => 'text',
'width' => '70px'
));
you have used 'type' => 'options' and not define options there
Best Answer
As you mentioned,
if the order was made using purchase order.So where do you persist that PO number. The link you have added here is calling PO number from payment table. If you are expecting that value then you can go ahead with the link else you'll need additional implementation.