Approve conditions written in PHP to MySQL SP

Good morning or nights for some. The following block of code works correctly and is written in PHP with the help of the Yii2 framework:

$subQuery = (new \yii\db\Query)
                ->select([
                    'p.FK_DOCUMENTO_ODC',
                ])
                ->from('tbl_periodos p')
                ->where(['YEAR(p.FECHA_INI)'=>intval($fecha_ini_anio)])
                ->andWhere(['not', ['p.FK_DOCUMENTO_ODC' => null]])
                ->orderBy('p.FK_DOCUMENTO_ODC DESC')->limit(1)->one();

            $query = (new \yii\db\Query)
                ->select([
                    'd.PK_DOCUMENTO',
                    'd.MONTO',
                    'd.NUMERO_PERIODOS',
                ])
                ->from('tbl_documentos d')
                ->where(['=','d.PK_DOCUMENTO',$subQuery['FK_DOCUMENTO_ODC']])
                ->orderBy('d.PK_DOCUMENTO DESC')->limit(1)->one();

            if($query){

                $mismo_pkDocumento = Tblperiodos::find()->where(['FK_DOCUMENTO_ODC' => $query['PK_DOCUMENTO']])->all();

                $cont_num_doc = count($mismo_pkDocumento);

                if($cont_num_doc < $query['NUMERO_PERIODOS']){

                    $modelDoc = TblDocumentos::find()->where(['PK_DOCUMENTO' => $query['PK_DOCUMENTO']])->limit(1)->one();

                    $nuevo_monto = $monto + $query['MONTO'];
                    $modelDoc->MONTO = $nuevo_monto;

                    $modelDoc->save(false);

                    $fecha_fin_nueva = transform_date($fechaFin,'Y-m-d');

                    $model->FECHA_INI=transform_date($fechaInicio,'Y-m-d');
                    $model->FECHA_FIN=$fecha_fin_nueva;
                    $model->TARIFA=$tarifa;
                    $model->HORAS=$horas;
                    $model->MONTO=$monto;
                    $model->FK_DOCUMENTO_ODC=$query['PK_DOCUMENTO'];
                    $model->FK_ASIGNACION=$keyAsig;
                    $model->FK_EMPLEADO=$asignacion->FK_EMPLEADO;

                    $model->FECHA_INGRESO=date('Y-m-d H:i:s');

                    $model->save(false);

                    if ($fecha_fin_nueva > $asignacion->FECHA_FIN) {
                        $asignacion->FECHA_FIN = $fecha_fin_nueva;
                        $asignacion->save(false);
                    }

                }

            }

Likewise within the SP I can leave the query in this way:

SELECT * FROM tbl_documentos d WHERE d.PK_DOCUMENTO = (SELECT p.FK_DOCUMENTO_ODC FROM tbl_periodos p WHERE YEAR(p.FECHA_INI) = YEAR(FECHA_INI_ANIO) AND p.FK_DOCUMENTO_ODC IS NOT NULL ORDER BY p.FK_DOCUMENTO_ODC DESC LIMIT 1) ORDER BY d.PK_DOCUMENTO DESC LIMIT 1

And this is where I have the doubt of how to save in a variable that query in the SP to be able to make the previous comparisons, if I found a register, count the found ones etc.