从年龄范围内的sql表客户端计数

<?php
$db_user = "*******";
$db= "mschyns_$db_user";
$db_pass = "*********";
$con=mysqli_connect("********",$db_user,$db_pass,$db);

if(mysqli_connect_errno()){
    echo "Failed to connect to MySQL: ".mysqli_connect_error();
}
    if ($Test = $con -> query("SELECT * FROM client")){
        mysqli_free_result($Test);
        }
    $Test = "SELECT sum(case when FLOOR(datediff(CURDATE(),date_birth)/365) < 15 then 1 else 0 end) as '1to15',
    sum(case when FLOOR(datediff(CURDATE(),date_birth)/365) >= 15 AND FLOOR(datediff(CURDATE(),date_birth)/365) < 30 then 1 else 0 end) as '15to30',
    sum(case when FLOOR(datediff(CURDATE(),date_birth)/365) >= 30 AND FLOOR(datediff(CURDATE(),date_birth)/365) < 45 then 1 else 0 end) as '30to60',
    sum(case when FLOOR(datediff(CURDATE(),date_birth)/365) >= 45 AND FLOOR(datediff(CURDATE(),date_birth)/365) < 60 then 1 else 0 end) as '45to60',
    sum(case when FLOOR(datediff(CURDATE(),date_birth)/365) >= 60 then 1 else 0 end) as '60' FROM client";
    echo "<table width=\"200\" class=\"list\">";
    echo "<tr>";
    echo "<th>Tranche d'age</th><th>Nombre de clients</th>";
    echo "</tr>";
    //while($row = mysqli_fetch_array($requete)){
    echo "<tr class=\"list\">";
    echo "<td class=\"list\">between 1 and 15</td><td class=\"list\">".$Test['1to15']."</td>";
    echo "</tr>";
    echo "<tr class=\"list\">";
    echo "<td class=\"list\">between 1 and 15</td><td class=\"list\">".$Test['15to30']."</td>";
    echo "</tr>";
    echo "<tr class=\"list\">";
    echo "<td class=\"list\">between 1 and 15</td><td class=\"list\">".$Test['30to45']."</td>";
    echo "</tr>";
    echo "<tr class=\"list\">";
    echo "<td class=\"list\">between 1 and 15</td><td class=\"list\">".$Test['45to60']."</td>";
    echo "</tr>";
    echo "<tr class=\"list\">";
    echo "<td class=\"list\">60+</td><td class=\"list\">".$Test['60']."</td>";
    echo "</tr>";
//}
echo "</table>";
mysqli_close($con);
?>

我有一个客户的生日列表,我想按年龄范围对他们进行排序 截至目前,我得到的结果是,遇到了格式错误的值