Q:

Sort order on custom column from customer grid

On my Admin side customer grid, i have a situacion, some times and some customers on column name i need First Name + Last Name, it's already done by magento core, but some customer i need just to print First name. Take a look on my Grid.php, i need take off last name from 'name' catenation, but when i remove from collection my column sort stop work.
<?php

class Mage_Adminhtml_Block_Customer_Grid extends Mage_Adminhtml_Block_Widget_Grid
{

public function __construct()
{
    parent::__construct();
    $this->setId('customerGrid');
    $this->setUseAjax(true);
    $this->setDefaultSort('entity_id');
    $this->setSaveParametersInSession(true);
}

protected function _prepareCollection()
{
    $collection = Mage::getResourceModel('customer/customer_collection')
        ->addNameToSelect()
        ->addAttributeToSelect('email')
        ->addAttributeToSelect('created_at')
        ->addAttributeToSelect('group_id')
        ->joinAttribute('billing_postcode', 'customer_address/postcode', 'default_billing', null, 'left')
        ->joinAttribute('billing_city', 'customer_address/city', 'default_billing', null, 'left')
        ->joinAttribute('billing_telephone', 'customer_address/telephone', 'default_billing', null, 'left')
        ->joinAttribute('billing_region', 'customer_address/region', 'default_billing', null, 'left')
        ->joinAttribute('billing_country_id', 'customer_address/country_id', 'default_billing', null, 'left');

    /*foreach($collection as $customer){
        preg_match("/[A-z| ]*//*", $customer->getName(), $name);
        $customer->setName($name[0]);
        unset($name);
    }*/

    $this->setCollection($collection);

    return parent::_prepareCollection();
}

protected function _prepareColumns()
{
    $this->addColumn('entity_id', array(
        'header'    => Mage::helper('customer')->__('ID'),
        'width'     => '50px',
        'index'     => 'entity_id',
        'type'  => 'number',
    ));

    /*
    $this->addColumn('firstname', array(
        'header'    => Mage::helper('customer')->__('First Name'),
        'index'     => 'firstname'
    ));
    $this->addColumn('lastname', array(
        'header'    => Mage::helper('customer')->__('Last Name'),
        'index'     => 'lastname'
    ));
    */

    $this->addColumn('name', array(
        'header'    => Mage::helper('customer')->__('Name'),
        'sortable'  => true,
        'index'     => 'name'
    ));

    $this->addColumn('email', array(
        'header'    => Mage::helper('customer')->__('Email'),
        'width'     => '150',
        'index'     => 'email'
    ));

    $groups = Mage::getResourceModel('customer/group_collection')
        ->addFieldToFilter('customer_group_id', array('gt'=> 0))
        ->load()
        ->toOptionHash();

    $this->addColumn('group', array(
        'header'    =>  Mage::helper('customer')->__('Group'),
        'width'     =>  '100',
        'index'     =>  'group_id',
        'type'      =>  'options',
        'options'   =>  $groups,
    ));

    $this->addColumn('Telephone', array(
        'header'    => Mage::helper('customer')->__('Telephone'),
        'width'     => '100',
        'index'     => 'billing_telephone'
    ));

    $this->addColumn('billing_postcode', array(
        'header'    => Mage::helper('customer')->__('ZIP'),
        'width'     => '90',
        'index'     => 'billing_postcode',
    ));

    $this->addColumn('billing_country_id', array(
        'header'    => Mage::helper('customer')->__('Country'),
        'width'     => '100',
        'type'      => 'country',
        'index'     => 'billing_country_id',
    ));

    $this->addColumn('billing_region', array(
        'header'    => Mage::helper('customer')->__('State/Province'),
        'width'     => '100',
        'index'     => 'billing_region',
    ));

    $this->addColumn('customer_since', array(
        'header'    => Mage::helper('customer')->__('Customer Since'),
        'type'      => 'datetime',
        'align'     => 'center',
        'index'     => 'created_at',
        'gmtoffset' => true
    ));

    if (!Mage::app()->isSingleStoreMode()) {
        $this->addColumn('website_id', array(
            'header'    => Mage::helper('customer')->__('Website'),
            'align'     => 'center',
            'width'     => '80px',
            'type'      => 'options',
            'options'   => Mage::getSingleton('adminhtml/system_store')->getWebsiteOptionHash(true),
            'index'     => 'website_id',
        ));
    }

    $this->addColumn('action',
        array(
            'header'    =>  Mage::helper('customer')->__('Action'),
            'width'     => '100',
            'type'      => 'action',
            'getter'    => 'getId',
            'actions'   => array(
                array(
                    'caption'   => Mage::helper('customer')->__('Edit'),
                    'url'       => array('base'=> '*/*/edit'),
                    'field'     => 'id'
                )
            ),
            'filter'    => false,
            'sortable'  => false,
            'index'     => 'stores',
            'is_system' => true,
    ));

    $this->addExportType('*/*/exportCsv', Mage::helper('customer')->__('CSV'));
    $this->addExportType('*/*/exportXml', Mage::helper('customer')->__('Excel XML'));
    return parent::_prepareColumns();
}

protected function _prepareMassaction()
{
    $this->setMassactionIdField('entity_id');
    $this->getMassactionBlock()->setFormFieldName('customer');

    $this->getMassactionBlock()->addItem('delete', array(
         'label'    => Mage::helper('customer')->__('Delete'),
         'url'      => $this->getUrl('*/*/massDelete'),
         'confirm'  => Mage::helper('customer')->__('Are you sure?')
    ));

    $this->getMassactionBlock()->addItem('newsletter_subscribe', array(
         'label'    => Mage::helper('customer')->__('Subscribe to Newsletter'),
         'url'      => $this->getUrl('*/*/massSubscribe')
    ));

    $this->getMassactionBlock()->addItem('newsletter_unsubscribe', array(
         'label'    => Mage::helper('customer')->__('Unsubscribe from Newsletter'),
         'url'      => $this->getUrl('*/*/massUnsubscribe')
    ));

    $groups = $this->helper('customer')->getGroups()->toOptionArray();

    array_unshift($groups, array('label'=> '', 'value'=> ''));
    $this->getMassactionBlock()->addItem('assign_group', array(
         'label'        => Mage::helper('customer')->__('Assign a Customer Group'),
         'url'          => $this->getUrl('*/*/massAssignGroup'),
         'additional'   => array(
            'visibility'    => array(
                 'name'     => 'group',
                 'type'     => 'select',
                 'class'    => 'required-entry',
                 'label'    => Mage::helper('customer')->__('Group'),
                 'values'   => $groups
             )
        )
    ));

    return $this;
}

public function getGridUrl()
{
    return $this->getUrl('*/*/grid', array('_current'=> true));
}

public function getRowUrl($row)
{
    return $this->getUrl('*/*/edit', array('id'=>$row->getId()));
}

}
Its wrong way i know, but have to get just first name and don't have other way. 
But now this make my sort on columns from grid stop work. I need sort working. 
If i remove this 3 lines from my _prepareCollection(), it's work fine but i need it too and with it don't work my sort. I'm crazy with this someone can help???
Ty in advise.

A:

You're best bet would be to load the firstname attribute on the collection and add that as an independent column. Adding column to customer grid in Magento - Data not populating will give you a good start. You should just need to add in ->addAttributeToSelect('firstname') and then add the column in the prepareColumns function...
$this->addColumn('firstname', array(
    'header'    => Mage::helper('customer')->__('First Name'),
    'index'     => 'firstname'
));

