How does \Magento\Framework\Data\Collection\AbstractDb::getSelectCountSql() work?

dmitry_fedyuk · April 29, 2016, 3:44pm

Context: How does \Magento\Eav\Model\ResourceModel\Entity\Attribute\Collection::getSelectCountSql() work?

magento/magento2/blob/958164/lib/internal/Magento/Framework/Data/Collection/AbstractDb.php#L223-L230


/**
 * Get SQL for get record count
 *
 * @return Select
 */
public function getSelectCountSql()
{
    $this->_renderFilters();

Details: How does \Magento\Framework\Data\Collection\AbstractDb::_renderFilters() work?

github.com

magento/magento2/blob/958164/lib/internal/Magento/Framework/Data/Collection/AbstractDb.php#L232-L233


$countSelect = clone $this->getSelect();
$countSelect->reset(\Magento\Framework\DB\Select::ORDER);

Details: How does \Zend_Db_Select::reset() work?

github.com

magento/magento2/blob/958164/lib/internal/Magento/Framework/Data/Collection/AbstractDb.php#L234-L238


$countSelect->reset(\Magento\Framework\DB\Select::LIMIT_COUNT);
$countSelect->reset(\Magento\Framework\DB\Select::LIMIT_OFFSET);
$countSelect->reset(\Magento\Framework\DB\Select::COLUMNS);


if (!count($this->getSelect()->getPart(\Magento\Framework\DB\Select::GROUP))) {

Details: How does \Zend_Db_Select::getPart() work?

github.com

magento/magento2/blob/958164/lib/internal/Magento/Framework/Data/Collection/AbstractDb.php#L239-L240


$countSelect->columns(new \Zend_Db_Expr('COUNT(*)'));
return $countSelect;

An example of the $countSelect->assemble() result:

SELECT COUNT(*) FROM `eav_attribute` AS `main_table`
	INNER JOIN `eav_entity_type` AS `entity_type`
		ON main_table.entity_type_id = entity_type.entity_type_id
	LEFT JOIN `eav_entity_attribute`
		ON main_table.attribute_id = eav_entity_attribute.attribute_id
	INNER JOIN `catalog_eav_attribute` AS `additional_table`
		ON main_table.attribute_id = additional_table.attribute_id
WHERE (`entity_type_code` = 'catalog_product') AND (`attribute_set_id` != '')