Magento – Hide a Grid’s Column in Backend

If you have a look at the renderer for the column type radio, Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Radio, you can see that there is no way to add an onclick event listener:

public function render(Varien_Object $row)
{
    $values = $this->getColumn()->getValues();
    $value  = $row->getData($this->getColumn()->getIndex());
    if (is_array($values)) {
        $checked = in_array($value, $values) ? ' checked="checked"' : '';
    } else {
        $checked = ($value === $this->getColumn()->getValue()) ? ' checked="checked"' : '';
    }
    $html = '<input type="radio" name="' . $this->getColumn()->getHtmlName() . '" ';
    $html .= 'value="' . $row->getId() . '" class="radio"' . $checked . '/>';
    return $html;
}

If you are looking to duplicate the functionality of the customer or product grid mass actions, have a look at the method Mage_Adminhtml_Block_Widget_Grid::_prepareMassactionColumn().
It adds a column with the type massaction.
It is called automatically whenever you add a mass action to a grid, but can also be used independently.

Please add below changes to your code.

You need to add GROUP BY entity_id.

Add select query on collection like below.

$collection->getSelect()->joinLeft(
    array('s' => new Zend_Db_Expr('(SELECT (o.grand_total - o.tax_amount) grand_excl_tax,'
        . ' FROM ' . Mage::getSingleton('core/resource')->getTableName('sales/invoice') . ' AS o'
        . ' GROUP BY entity_id)')),
    "s.entity_id = main_table.entity_id",
    array('grand_excl_tax')
);

After that add filter_index in addColumn:

$this->addColumn('grand_excl_tax', array(
    'header'    => Mage::helper('customer')->__('Amount Excl. Tax'),
    'index'     => 'grand_excl_tax',
    'filter_index' => 's.grand_excl_tax',
    'type'      => 'currency',
    'align'     => 'right',
    'currency'  => 'order_currency_code',
));

I am tested it and it's working fine form me, After applying this there is not any issue on grid filter.

Let me know still if you face any issue.