How to achieve this sorting described using mySQL and PHP?

Question

I have this table named "categories" with three fields as below

cat     | order | id
--------|-------|----
News    |  3    | 23
Hi-Tech |  2    | 15
Biz     |  5    | 8
Health  |  1    | 3

Also, I have another table named "links" like below

link    | order | cat-id
--------|-------|-------
link1   |  2    | 23
link2   |  8    | 15
link3   |  5    | 8
link4   |  6    | 15
link5   |  2    | 15
link6   |  4    | 23
link7   |  1    | 3
link8   |  1    | 8

What I want to achieve is to sort categories and below each category to sort the links of that category cat-id / id like this below:

Health
link7

Hi-Tech
link5
link4
link2

News
link1
link6

Biz
link8
link3

I succeeded on showing the categories sorted but I am loosing it after it.

My aim is to show this on a page so I guess I have to use PHP and mySQL.

Answer 1

The query is simply this:

SELECT c.cat, l.link, c.id
FROM links l INNER JOIN categories c
ON l.cat-id = c.id
ORDER BY c.`order`, l.`order`

And here it is at work.

In order to show it on a page, it would look like this:

mysql_connect(<host>, <username>, <password>);

$q = mysql_query("<query from above>");
$last_cat = 0;
while($row = mysql_fetch_assoc($q)) {
    if($row['id'] != $last_cat) {
        print '<h3>' . $row['cat'] . '</h3>';
        $last_cat = $row['id'];
    }
    print $row['link'] . '<br>';
}