codeigniter $this->db->where(); custom string problem

问题

Im trying to select some values using a custom string. below is my code

  $this->db->from('posted');
  $st="infor='rent' AND (typeq='in' OR typeq='out')";
  $this->db->where($st);  
  $q = $this->db->get();  

A Database Error Occurred

Error Number: 1054

Unknown column ‘infor=‘rent’’ in ‘where clause’
SELECT * FROM (`posted_ads`) WHERE `infor=‘rent’` AND (typeq=‘in’
 OR typeq=‘out’)
Filename: C:\wamp\www\parklot\system\database\DB_driver.php
Line Number: 330

i think the problem is coz of

WHERE `infor='rent'` 

when i manualy execute this code it works perfectly.

WHERE infor='rent' 

how do i get rid of

`` 

because its automatically added

回答1:

Add a third parameter to the where() and set it to FALSE

  $this->db->from('posted');
  $st="infor='rent' AND (typeq='in' OR typeq='out')";
  $this->db->where($st, NULL, FALSE);  
  $q = $this->db->get();

$this->db->where() accepts an optional third parameter. If you set it to FALSE, CodeIgniter will not try to protect your field or table names with backticks.

CodeIgniter Documentation

回答2:

While the solution works I wanna add: Be careful! You need to secure your query and escape all values! If you like to use the Query Builder

$q = $this->db->select('*')->from('posted_ads')
    ->where('infor', 'rent')
    ->or_group_start()
            ->where('typeq', 'in')
            ->where('typeq', 'out')
    ->group_end()
->get();

This way Codeigniter takes care of proper escaping.

来源：https://stackoverflow.com/questions/7547731/codeigniter-this-db-where-custom-string-problem