Print data from databaseto webpage problem

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PHP

MySQL

hi
I wrote this code to show data from data base in my webpage
this is my code:

@ $db=mysql_pconnect('localhost','bookshop');
        if (!$db)
        {
            echo 'Error: coud not connect to database. please try again later.';
            exit;
        }
        mysql_select_db('bookshop');
        $query="select * from books where ".$searchtype." like '%".$searchterm."%'";
        $result=mysql_query($query);
        $num_results=mysql_num_rows($result);
        echo '<p>Number of books found: '.$num_results.'</p>';
        for ($i=0;$i<1;$i++)
        {
            $row=mysql_fetch_array($result);
            echo '<p><strong>'.($i+1).'.title: ';
            echo htmlspecialchars(stripslashes($row['title']));
            }

but I had this erors

Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in D:\xampp\htdocs\chapter1\resultpage.php on line 35
Warning: mysql_fetch_array() expects parameter 1 to be resource, boolean given in D:\xampp\htdocs\chapter1\resultpage.php on line 39

what can I do with this problem
I checked result with mysql_eror() function and I saw this message: No database selected how I can select the database