How SELECT `e`.* is coming in Query while printing collection filter in magento 1.9

Question

$collection = Mage::getModel("customer/customer")->getCollection()
             ->addAttributeToSelect('firstname')
             ->addAttributeToFilter('grisk_college_new_id', array('in' =>$collegeid))
             ->addFieldToFilter('group_id', array('in' => array(4, 5)))
             ->addAttributeToFilter('physical_verify', array('null' => true), 'left')
             ->addFieldToFilter('assigned_campus_manager',array('like' => '%_/' . $custid . "%")); 

SELECT e.*, at_grisk_college_new_id.value AS grisk_college_new_id, at_physical_verify.value AS physical_verify, at_assigned_campus_manager.value AS assigned_campus_manager FROM customer_entity AS e INNER JOIN customer_entity_int AS at_grisk_college_new_id ON (at_grisk_college_new_id.entity_id = e.entity_id) AND (at_grisk_college_new_id.attribute_id = '275') LEFT JOIN customer_entity_int AS at_physical_verify ON (at_physical_verify.entity_id = e.entity_id) AND (at_physical_verify.attribute_id = '209') INNER JOIN customer_entity_varchar AS at_assigned_campus_manager ON (at_assigned_campus_manager.entity_id = e.entity_id) AND (at_assigned_campus_manager.attribute_id = '183') WHERE (e.entity_type_id = '1') AND (at_grisk_college_new_id.value IN('')) AND (e.group_id IN(4, 5)) AND (at_physical_verify.value IS NULL) AND (at_assigned_campus_manager.value LIKE '%_/%')

How can I make it more efficient ?

Answer 1

Use reset function:

$collection = Mage::getModel("customer/customer")->getCollection()
                 ->addAttributeToFilter('grisk_college_new_id', array('in' =>$collegeid))
                 ->addFieldToFilter('group_id', array('in' => array(4, 5)))
                 ->addAttributeToFilter('physical_verify', array('null' => true), 'left')
                 ->addFieldToFilter('assigned_campus_manager',array('like' => '%_/' . $custid . "%"));

    $collection ->getSelect()
     ->reset(Zend_Db_Select::COLUMNS)
     ->columns('firstname');