Codeigniter: Weird behaviour of $this->db->like()

问题

I've written a simple query for searching a keyword in the database.

$keyword = "keyword sample"; 
$keyword = str_replace(" ", "%", $keyword);   

$this->db->select('*')->from('table')
           ->like('column', "%".$keyword."%")->get();

Now the query generated by Codeigniter is like this:

SELECT * FROM (`table`) WHERE `column` LIKE '%keyword\%sample%'

Where is the trailing \ coming from in the query? This is making an erroneous search and not returning the data that is actually in the db. I've checked everything and nothing seems to be wrong with the code I've written. Please help!

回答1:

If you dig a bit into CodeIgniter's internals, you'll notice that the $this->db->like() function escapes special characters it contains - including, of course, %.

I don't think like() will help you much with your particular needs. Your best bet, I guess, would be to bypass the problem and use a where function containing your LIKE clause:

$this->db->select('*')->from('table')->where("column LIKE '%$keyword%'")->get()->result_array();

回答2:

You just try it like this:

$this->db->select('*')
$this->db->from('table');
$this->db->like('column', $keyword);
return $this->db->get()->result_array();

If you want to control where the wildcard (%) is placed, you can use an optional third argument. Your options are 'before', 'after' and 'both' (which is the default).

example:

$this->db->select('*')
$this->db->from('table');
$this->db->like('column', $keyword, 'before');
return $this->db->get()->result_array();

If you do not want to use the wildcard (%) you can pass to the optional third argument the option 'none'.

example:

$this->db->select('*')
$this->db->from('table');
$this->db->like('column', $keyword, 'none');
return $this->db->get()->result_array();

BUT, for your example you must need to search like "%keyword sample%", or like "%keyword%" OR "%simple%";

For example:

$this->db->like('column', 'keyword simple');
// Produces: WHERE column LIKE '%keyword simple%'

$this->db->like('column', 'keyword');
$this->db->or_like('column', 'simple');
// Produces: WHERE column LIKE '%keyword%' OR column LIKE '%simple%'

More, you can read CodeIgniter User Guide

回答3:

Use the escape_like_str() method.

The escape_like_str() method should be used when strings are to be used in LIKE conditions so that LIKE wildcards %, _ in the string are also properly escaped. It cannot automatically add the ESCAPE ! condition for you, and so you’ll have to manually do that.

Hope it helps.

$keyword = "keyword sample"; 
$sql = "SELECT id FROM table WHERE column LIKE '%" .
$this->db->escape_like_str($keyword)."%' ESCAPE '!'";

Source:- https://www.codeigniter.com/userguide3/database/queries.html

来源：https://stackoverflow.com/questions/22544195/codeigniter-weird-behaviour-of-this-db-like

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