EncountersCtrl

public function bmiGraphApi($patient_id) {

        if(!empty($patient_id)) {
            $query = $this->Encounters->find()
                ->join(['Patients']);
            $time = $query->func()->date_format([
                'Encounters.visitdate' => 'identifier',
                "'%m-%d-%y'" => 'literal'
            ]);
            $data = $query->select([ 'visitdate' => $time, 'bmi' => 'Patients.bmi'])
                ->where(['Encounters.patient_id' => $patient_id])
                ->order(['Encounters.id' => 'DESC'])
                ->limit(15);
            //debug($data); exit;
        }
        $this->set(compact('data'));
    }