Displaying results as hyperlinks to an additional query?

I've been looking for a way to display MySQL results as hyperlinks that will perform another query when clicked.

Say I have a 2 tables in my database linked by ALTER TABLE topics ADD FOREIGN KEY(topic_cat) REFERENCES categories(cat_id) ON DELETE CASCADE ON UPDATE CASCADE;

categories:

+-----------------+--------------+------+-----+---------+----------------+
| Field           | Type         | Null | Key | Default | Extra          |
+-----------------+--------------+------+-----+---------+----------------+
| cat_id          | int(8)       | NO   | PRI | NULL    | auto_increment |
| cat_name        | varchar(255) | NO   | UNI | NULL    |                |
| cat_description | varchar(255) | NO   |     | NULL    |                |
+-----------------+--------------+------+-----+---------+----------------+

topics:

+---------------+--------------+------+-----+---------+----------------+
| Field         | Type         | Null | Key | Default | Extra          |
+---------------+--------------+------+-----+---------+----------------+
| topic_id      | int(8)       | NO   | PRI | NULL    | auto_increment |
| topic_subject | varchar(255) | NO   |     | NULL    |                |
| topic_date    | datetime     | NO   |     | NULL    |                |
| topic_cat     | int(8)       | NO   | MUL | NULL    |                |
| topic_by      | int(8)       | NO   | MUL | NULL    |                |
+---------------+--------------+------+-----+---------+----------------+

I also have a PHP search form that queries the table "categories":

$var = @$_GET['search'] ;开发者_Go百科
  $trimmed = trim($var);

$query = "select * from categories where cat_name like \"%$trimmed%\"  
  order by cat_name";

I want to be able to display the results of the above query as hyperlinks and when clicked, I want to display results that are linked to "cat_name" by "topic_cat" and "cat_id". I can't seem to find an example of this anywhere online. Any suggestions?

When you output results, do
print ("<a href='show_category_topics.php?id=".$row["cat_id"]."'>".$row["cat_name"]."</a>");

On a new page (show_category_topics.php) run the query
$query = "SELECT * FROM topics WHERE topic_cat ='".mysql_real_escape_string($_GET["id"])."'"; and print results.

You can also use ajax calls to php pages.