PHP - Sumar cantidad con un criterio de fecha

<?php

    include 'cn.php';

    $query="SELECT SUM(monto) as `total` FROM tabla1 WHERE fecha BETWEEN '2019-01-00' AND '2019-01-31'";

    $res=mysqli_query($conexion,$query);

    $data=mysqli_fetch_array($res);

    echo number_format($data['total'],2)

?>

$query="SELECT SUM(monto) as `total` FROM tabla1 WHERE YEAR(fecha)=2019 AND MONTH(fecha)=1";