Comparing data from two databases in cakephp

Question

I would like to write the following in CakePHP:

(select email
 from membersdatabase
 where memberid not in
   (select memberid from deregisteredmembers) 

Answer 1

From the model of membersdatabase, write the below query:

$options = array(
        'conditions' => array('deregisteredmembers.memberid is null'),
        'joins' => array(
            array(
                'alias' => 'deregisteredmembers',  
                'table' => 'deregisteredmembers',
                'type' => 'LEFT',
                'conditions' => array(
                    'deregisteredmembers.memberid = membersdatabase.id',
                ),
            )
        ),
        'fields' => array('membersdatabase.email')
    );

$this->find('all',$options);

You will get desired result