GROUP_CONCAT MAX LENGHT

<?php
   define('DB_SERVER', 'localhost');
   define('DB_USERNAME', 'root');
   define('DB_PASSWORD','root');
   define('DB_DATABASE', 'test');
   $db = mysqli_connect(DB_SERVER,DB_USERNAME,DB_PASSWORD,DB_DATABASE);
$access ='PROGRAMMER';
$result = mysqli_query($db,"SET SESSION group_concat_max_len = 100000000") or die(mysqli_error($db));
$sql ="SELECT group_concat(concat('\'',REPLACE(code,'-',''),'\'')) code

FROM (select code from expense_acct
    ) mydata";
$result = mysqli_query($db,$sql) or die(mysqli_error($db));
$row = mysqli_fetch_array($result);
echo $row['code'];



?>