How to make a Join on query with Cakephp?

Question

I have Comments table where a user can comment on another user like this :

And these are constraints :

When I use this query :

$comments = TableRegistry::getTableLocator()
            ->get('Comments')
            ->find('all');
 $query = $comments
          ->find('all')
          ->contain(['Users']);

It retrieves the comment but it applies the join only on commented_id . While I want to retrieve The comment object containing its two related users one as commentator , the other as commented ,; So how to build the query ?

This is the CommentsTable :

class CommentsTable extends Table
{
    /**
     * Initialize method
     *
     * @param array $config The configuration for the Table.
     * @return void
     */
public function initialize(array $config)
{
    parent::initialize($config);

    $this->setTable('comments');
    $this->setDisplayField('id');
    $this->setPrimaryKey('id');

    $this->belongsTo('Users', [
        'foreignKey' => 'commentator_id',
        'joinType' => 'INNER'
    ]);
    $this->belongsTo('Users', [
        'foreignKey' => 'commented_id',
        'joinType' => 'INNER'
    ]);
}

/**
 * Default validation rules.
 *
 * @param \Cake\Validation\Validator $validator Validator instance.
 * @return \Cake\Validation\Validator
 */
public function validationDefault(Validator $validator)
{
    $validator
        ->integer('id')
        ->allowEmpty('id', 'create');

    $validator
        ->scalar('content')
        ->maxLength('content', 255)
        ->requirePresence('content', 'create')
        ->notEmpty('content');

    $validator
        ->integer('score')
        ->requirePresence('score', 'create')
        ->notEmpty('score');

    $validator
        ->dateTime('created_at')
        ->requirePresence('created_at', 'create')
        ->notEmpty('created_at');

    $validator
        ->dateTime('updated_at')
        ->requirePresence('updated_at', 'create')
        ->notEmpty('updated_at');

    return $validator;
}

/**
 * Returns a rules checker object that will be used for validating
 * application integrity.
 *
 * @param \Cake\ORM\RulesChecker $rules The rules object to be modified.
 * @return \Cake\ORM\RulesChecker
 */
public function buildRules(RulesChecker $rules)
{
    $rules->add($rules->existsIn(['commentator_id'], 'Users'));
    $rules->add($rules->existsIn(['commented_id'], 'Users'));

    return $rules;
}

}

Answer 1

Chnage your relationships to something like this:

$this->belongsTo('Commenters', [
    'className' => 'Users',
    'foreignKey' => 'commentator_id',
    'joinType' => 'INNER'
]);
$this->belongsTo('Users', [
    'foreignKey' => 'commented_id',
    'joinType' => 'INNER'
]);

So then you can contain the two different relationships.

$comments = TableRegistry::getTableLocator()
        ->get('Comments')
        ->find('all')
        ->contain(['Commenters', 'Users']);

And access them like this:

$comment->commenter->name; // Name of the person who commented
$comment->user->name; // Name of the person who was commented on

Answer 2

I'm not sure exactly what output you what but as per my understanding you can use custom join for the same:

$data = $this->Comments->find()
                        ->join([
                          'Users' => [
                                          'table' => 'users',
                                          'type' => 'INNER',
                                          'conditions' => [
                                              'Users.id=Comments.commentator_id',
                                           'OR' => [
                                                'Users.id=Comments.commented_id'
                                                   ]
                                            ] 
                                     ]
                              ]);

or you can modify this as per your need.

https://book.cakephp.org/3.0/en/orm/query-builder.html#adding-joins

Hope this will help.