$sql = "SELECT sale_total, SUM(sale_total) AS total FROM sale WHERE `sale_date_M` = '$bir_M';";
$result = $conn->query($sql);
$row = $result->fetch_array();
echo $row['total'];
$sql = "SELECT sale_total, SUM(sale_total) AS total FROM sale WHERE `sale_date_M` = '$bir_M';";
$result = $conn->query($sql);
$row = $result->fetch_array();
echo $row['total'];