Magento Sales Order Grid shows incorrect number of records when added Names and Skus columns

Question

I'm working with Magento version 1.4 and I added extra grid columns (names and skus) to Sales Order Grid, the returned data is correct but I'm having problems with pagination and total number of records, my code as follow:

First I Edited Mage_Adminhtml_Block_Sales_Order_Grid:

protected function _prepareCollection()
{
    $collection = Mage::getResourceModel($this->_getCollectionClass())
    ->join(
        'sales/order_item',
        '`sales/order_item`.order_id=`main_table`.entity_id',
        array(
            'skus'  => new Zend_Db_Expr('group_concat(`sales/order_item`.sku SEPARATOR ", ")'),
            'names' => new Zend_Db_Expr('group_concat(`sales/order_item`.name SEPARATOR ", ")'),
            )
        );
    $collection->getSelect()->group('entity_id');

    $this->setCollection($collection);
    return parent::_prepareCollection();
}

Then I override this method to return correct results when filter by names or skus

    protected function _addColumnFilterToCollection($column)
{
    if($this->getCollection() && $column->getFilter()->getValue()) 
    {
        if($column->getId() == 'skus'){
            $this->getCollection()->join(
                'sales/order_item',
                '`sales/order_item`.order_id=`main_table`.entity_id',
                array(
                    'skus'  => new Zend_Db_Expr('group_concat(`sales/order_item`.sku SEPARATOR ", ")'),
                )
            )->getSelect()
                ->having('find_in_set(?, skus)', $column->getFilter()->getValue());

            return $this;
        }

        if($column->getId() == 'names'){
            $this->getCollection()->join(
                'sales/order_item',
                '`sales/order_item`.order_id=`main_table`.entity_id',
                array(
                    'names' => new Zend_Db_Expr('group_concat(`sales/order_item`.name SEPARATOR ", ")'),
                )
            )->getSelect()
                ->having('find_in_set(?, names)', $column->getFilter()->getValue());

            return $this;
        }
    }
    return parent::_addColumnFilterToCollection($column);
}

Then I edited this method getSelectCountSql() in Mage_Sales_Model_Mysql4_Order_Collection class:

public function getSelectCountSql()
{
    $countSelect = parent::getSelectCountSql();

    //added 
    $countSelect->reset(Zend_Db_Select::HAVING);
    //end

    $countSelect->resetJoinLeft();
    return $countSelect;
}

How can I calculate number of rows?

Answer 1

Maybe its a bit to late but in your code try using GROUP insted of HAVING:

$countSelect->reset(Zend_Db_Select::GROUP);

Because you are using this statemen:

$collection->getSelect()->group('entity_id');