Как работать со связанными таблицами в Yii2?

public function getAttrs()
    {
        return $this
            ->hasMany(Profile::className(), ['user_id' => 'id'])
            ->where('name = "name"')->union(
                $this->hasMany(Profile::className(), ['user_id' => 'id'])->where('name = "surname"')
            );
    }

return $this->hasMany(User::className(), ['id' => 'u_id1'])
->viaTable('UserContacts', ['id' => 'u_id1'])->union($this->hasMany(User::className(), ['id' => 'u_id2'])
->viaTable('UserContacts', ['id' => 'u_id2']));

return $this->hasMany(User::className(), ['id' => 'u_id2'])
->viaTable(UserContact::tableName(), ['u_id1' => 'id']);