未知列自动添加到where子句codeigniter查询中

Question

未知列session_id自动添加到where子句codeigniter查询中。

Error Number: 1054
Unknown column 'session_id' in 'where clause'
SELECT `column` FROM (`table_name`) WHERE `session_id` = '30d111cf75477d3f7a67a7d88469f3c4' AND `id` = 1 LIMIT 1
Filename: /var/www/site/www/libraries/acl.php
Line Number: 41,

这是我的查询=＆gt;

$this->ci->db->select('column');
$this->ci->db->where('id',floatval($data));
$sql = $this->ci->db->get('table_name',1);

但是当我使用直接查询时它工作正常.....