传递数据出错了吗？

狮子座百分之99

view中  ： 标题：<?=anchor("message/enter/$row->id","$row->title");?>
点击后url：http://localhost/ci/index.php/message/enter/17,

controller的enter（）：
$id = $this->uri->segment(3);
$sql = 'select * from entries where id = '+$id;
$data['message'] = $this->db->query($sql);
出现错误：
A Database Error Occurred

Error Number: 1064

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '17' at line 1

17

Filename: C:\wamp\www\ci\system\database\DB_driver.php

Line Number: 330

太尉天上飞

$sql = 'select * from entries where id = '+$id;

=》

$sql = 'select * from entries where id = '.intval($id);

狮子座百分之99

太尉天上飞 发表于 2012-8-26 01:10
$sql = 'select * from entries where id = '+$id;

=》

谢谢~

守望幸福的孩子

链接字符串问题，“+”是js链接字符串；“.”是php程序链接字符串。。。。