test query for join

$this->getCollection()->addFieldToSelect('couponsunique_id');
$this->getCollection()->getSelect()->joinLeft(array('C' =>  'coupons_code_log'), 'main_table.couponsunique_id = C.coupon_parent_id');
$this->getCollection()->getSelect()->group('C.coupon_parent_id');
$this->getCollection()->getSelect()->having('count(couponslog_id) = ?', $value);

protected function _supplierFilter($collection, $column)
    {
$value = $column->getFilter()->getValue();
        if (!$value):
return $this;
        else:
$this->getCollection()->addFieldToSelect('couponsunique_id');
$this->getCollection()->getSelect()->joinLeft(array('C' =>  'coupons_code_log'), 'main_table.couponsunique_id = C.coupon_parent_id');
$this->getCollection()->getSelect()->group('C.coupon_parent_id');
$this->getCollection()->getSelect()->having('count(couponslog_id) = ?', $value);
        endif;

        return $this;
    }

 $this->addColumn('count', array(
          'header'    => Mage::helper('couponsunique')->__('Count'),
          'align'     =>'left',
          'index'     => 'couponsunique_id',
 'filter_condition_callback' => array($this, '_supplierFilter'),
 'renderer'  => 'Magenext_Couponsunique_Block_Renderer_Count'
      ));