Добавлять ключ-значение в массив без перезаписи

while {...
    echo массив[id].' '.массив['name'].' '.массив['message'];
}

$arr = array(
  0 => array('id' => 5, 'name' => 2, 'message' => 'qweqwe'),
  1 => array('id' => 7, 'name' => 1, 'message' => 'ewqewq')
);
$cnt = count($arr);
for($i = 0; $i < $cnt; $i++){
  echo $arr[$i]['id'],', ', $arr[$i]['name'],', ', $arr[$i]['message'],'<br />';
  //и тд
}

<?php
$a = [
    ['id' => 5, 'name' => 2, 'message' => 'qweqwe'],
    ['id' => 7, 'name' => 1, 'message' => 'ewqeqw'],
];
 
foreach ($a as $v)
    printf("%s %s %s<br>".PHP_EOL, $v['id'], $v['name'], $v['message']);

if ($qwe != '')
{
    добавить в массив данные
}

$rez = mysql_query("SELECT * FROM `crm_kassa` ORDER BY `id` desc LIMIT $offset, 30");
while($r = mysql_fetch_assoc($rez))
{
echo $r['name']; //Такого вида вывод
}

$arr = [];
$rez = mysql_query("SELECT * FROM `crm_kassa` ORDER BY `id` desc LIMIT $offset, 30");
while($r = mysql_fetch_assoc($rez)){
  $arr[]['id'] = $r['id'];
  $arr[]['name'] = $r['name'];
  $arr[]['message'] = $r['message'];
}
//или так
$arr = [];
$i = 0;
$rez = mysql_query("SELECT * FROM `crm_kassa` ORDER BY `id` desc LIMIT $offset, 30");
while($r = mysql_fetch_assoc($rez)){
  $arr[$i]['id'] = $r['id'];
  $arr[$i]['name'] = $r['name'];
  $arr[$i]['message'] = $r['message'];
  $i++;
}

$arr = [];
$result = mysql_query("SELECT `id`, `name`, `message` FROM `crm_kassa` ORDER BY `id` DESC LIMIT $offset, 30")
    or die(mysql_error());
while ($row = mysql_fetch_assoc($result))
    $arr[] = $row;