Left Join CakePHP3 - sql

Question

I'm trying to do a LEFT JOIN in CakePHP3.
But all I get is a "is not associated"-Error.
I've two tables BORROWERS and IDENTITIES.
In SQL this is what I want:
SELECT
identities.id
FROM
identities
LEFT JOIN borrowers ON borrowers.id = identities.id
WHERE
borrowers.id IS NULL;
I guess this is what I need:
$var = $identities->find()->select(['identities.id'])->leftJoinWith('Borrowers',
function ($q) {
return $q->where(['borrowers.id' => 'identities.id']);
});
But I'm getting "Identities is not associated with Borrowers".
I also added this to my Identities Table:
$this->belongsTo('Borrowers', [
'foreignKey' => 'id'
]);
What else do I need?
Thanx!

Answer 1

The foreign key cannot just be 'id', that's not a correct model association. You'd need to put a 'borrower_id' field in identities, and declare it like this in the Identities model:
class Identities extends AppModel {
var $name = 'Identities';
public $belongsTo = array(
'Borrower' => array (
'className' => 'Borrower',
'foreignKey' => 'borrower_id'
)
);
Note the capitalization and singular/plural general naming conventions which your example doesn't follow in the least - ignoring those will get you some really hard to debug errors..

Answer 2

Yup. It was an instance of \Cake\ORM\Table, due to my not well chosen table name (Identity/Identities). I guess it's always better not to choose those obstacles, for now I renamed it to Label/Labels.
This query now works perfectly:
$var = $identities
->find('list')
->select(['labels.id'])
->from('labels')
->leftJoinWith('Borrowers')
->where(function ($q) {
return $q->isNull('borrowers.id');
});