Return to Revisions

use protected function _applyMyFilter(Varien_Data_Collection_Db $collection, Mage_Adminhtml_Block_Widget_Grid_Column $column) {

$select = $collection->getSelect();
$field = $column->getIndex();
$value = $column->getFilter()->getValue();
$select->where("invoice.grand_total - invoice.tax_amount>?", $value['from']);
$select->where("invoice.grand_total - invoice.tax_amount<?", $value['to']);

}