How to count file of category in Codeigniter
<p>I have 2 table data:</p>

<p>db_category: <br/>
+idcategory<br/>
+name <br/>
db_book:<br/>
+ idbook<br/>
+ name<br/>
+ idcategory<br/></p>

<p>Now I want show count of book by category, explample:<br/>
  book 1 : 2 file<br/>
  book 2 : 2 file<br/>
Please help me, thanks</p>