$ids=array(1,2,3,4);
$sql_mul = "SELECT * FROM `usertable` WHERE `id` IN (" . implode(',', $ids) . ")";
$query_mul = $this->db->query($sql_mul);
$row_mul = $query_mul->result_array();
foreach ($row_mul as $k => $val) {
$host = $val['host'];
${"row_$host"}[$k] = $val;
//TODO 变量中添加变量,变量中的变量
}
print_r($row_xxx);