title: codeigniter add wrong extra quote in query
body: <p>Please Help me to solve this problem..</p>
  
  <p>i'm going to do query in mysql but code igniter read my query in wrong format:</p>
  
  <p><strong>my query :</strong> </p>
  
  <pre><code>$this-&gt;db-&gt;select('substring(sbj_prog,1,5) as prog , count(sbj_prog) as bil');
  $this-&gt;db-&gt;from('sbj_app');
  $this-&gt;db-&gt;group_by('prog');
  $this-&gt;db-&gt;limit('10');
  </code></pre>
  
  <p><strong>this is how codeigniter read</strong></p>
  
  <pre><code> SELECT substring(sbj_prog, `1`, `5)` as prog, count(sbj_prog) as bil FROM (`sbj_app`) GROUP BY `prog` LIMIT 10
  </code></pre>
  
  <p>the problem is why the extra quote is added to the <code>5)</code></p>
  
  <p>Thank you very much.</p>