I found a strange bug/feature in MySQL which means that if you do a select statement using a INT against a VARCHAR column in matches all of the values in the column which do not start with a number. MySQL claim this is a normal.

So if I had a table like:

  id int(11) unsigned NOT NULL auto_increment,
  whom varchar(100) default NULL,
  task varchar(100) default NULL
  created_date timestamp NULL default NULL,

And then had a query:

SELECT id FROM tasks WHERE whom="Dale" AND task=0

You would get a match.

So you are saying right now, well you should escape your query, you are right though consider this:

CodeIgniter active db select:

$this->db->where(array('whom'=>$this->uri->segment(2), 'task'=>$this->uri->segment(3)));
echo $this->db->last_query();

And there is the hole in CodeIgniter exists if the segment in the URI does not exist, as it returns 0 as an INT if say someone puts in the URL http://example.com/tasks/dale

The solution is to explicitly convert the URI segments into strings:

$whom = (string) $this->uri->segment(2);
$task = (string) $this->uri->segment(3);
$this->db->where(array('whom'=>$whom, 'task'=>$whom));
echo $this->db->last_query();

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