当查询包含字符“（”或字符“）”时，SQL查询返回phpMyAdmin上的结果但不返回Codeigniter中的结果

Question

$sql = "SELECT * FROM apps as a"; 
$where = array();
if(isset($filter['app_name']) && $filter['app_name'] != '0') { 
    $app_name = addslashes($filter['app_name']); 
    $collate = get_collate($filter['app_name']); 
    $where[] = "LOWER(a.name) $collate LIKE LOWER('%" . mysql_real_escape_string($app_name). "%')"; } 
if ($where){ 
    $sql .= " WHERE " . implode(" AND ", $where); 
} 
$query = $this->db->query($sql); 
return $query->result();

如果param $ filter ['app_name']包含字符“（”或“）”来自codeigniter的$ query-＆gt; result（）返回null但是如果我在PhpMyAdmin中直接查询它返回结果。请帮我修复这个问题。 TKS。