Question

probably a straightforward to the trained eye but I have agonised over this for too long now..

I have two db tables designed to generate RSS feeds to the browser: ‘Channel’ and ‘Item’:

---

**Channel Table**  Primary Key: Id
Id   Title       Desc         Link
1    News        latest       www...
2    Sport       latest       www...
3    Gossip      latest       www..

As you can see there is more than one channel, which is central to my query..

**Item Table** Primary Key: Id, Index Key: Chan_Id
Id   Title       Desc         Link   Chan_Id
1    Footie      Liv-ManU1    www...    2
2    Cricket     India-Eng..  www...    2
3    G5 Summit   G5 Talks..   www...    1
4    X-Factor    Simon Cowell.www...    3
5    Iraq        MOD says...  www...    1
6    M Jackson   Court trial..www...    3

---

Now I have seen scripts where an RSS feed can be displayed thru PHP and it works great – the main problem is all examples I have seen assumes you have only One channel to attach your items to..

News

G5 Summit   G5 Talks......  
Iraq        MOD says......  

seeing as I have more than one channel, what I am looking for is to first print out multiple channels with related content:

News
G5 Summit   G5 Talks......  
Iraq        MOD says......  

Sport
Footie      Liv-ManU1.....  
Cricket     India-Eng.....  

Gossip
X-Factor    Simon Cowell..  
M Jackson   Court trial..   

then ultimately dump this data into separate xml files, depending on subject matter (Footie.xml, Cricket.xml, etc.) This part just needs a little fine tuning, as I have a formula for this using PHP DOM to construct and save:

$doc->save(row['chan_title']) 

not the exact syntax but method I use works, but shows only channels NOT items. The central issue is two-fold:

1. SQL Query: how would I go about selecting the data from the db, as a join? If so, an Inner Join similar to this:

   SELECT Channel.Id, Channel.Title, Item.Title, Item.Desc, Item.Chan_Id
   FROM Channel
   INNER JOIN Item
   ON Channel.Id=Item.Chan_Id
   ORDER BY Channel.Id

or maybe use a sub-query?

1. How do I then get the data from two tables and display it with PHP? Would it be easier to wrap up methods in classes and do it that way? I’ve tried to use a while( channel query) inside while( item query) inside foreach( item) but only displayed channel info. Possibly the wrong permutation but I’ve been experimenting with a view of finding a solution but need some expert help so I can move on!!

Your help will be appreciated, I will try and respond as soon as I can.

EDIT – Wow, 2 days and no response, can’t be that hard!! Well actually, it isn’t. I didn’t need it to be so complicated, the main point was more about the correct syntax. Still not found a true solution but getting close – I decided to use two queries, with two while statements, one inside the other:

$detQry = sprintf("SELECT * FROM ".$detailsTable);
$itQry = sprintf("SELECT id, title, description FROM ".$itemsTable." WHERE chan_id = ".$detailsTable.".id ORDER BY chan_id ASC LIMIT 0, 30 ");
$result = mysql_query($detQry) OR die ('Could not execute query: ' . mysql_error());
$run = mysql_query($itQry) OR die ('Could not execute query: ' . mysql_error());

while($row = mysql_fetch_assoc($result)) {
echo $row['title'].'<br>';
echo $row['description'].'<br><br>';

while(list($ttl, $dsc, $pbd) = mysql_fetch_array($run)) {
    echo $ttl.'<br>';
    echo $dsc.'<br><br>';
    echo $pbd.'<br><br><br>';
}
}

Problem is, when I run this script only the Channel ‘title ‘ and ‘description’ print.. what am I not doing to make this work? Could it be to do with the list() statement?

Any help welcomed to shorten the agony…

EDIT 2 – Resolved, thanks to a suggestion from Woody. It took a long time, but finally got the specific result I was looking for after I tested the formula given by Woody. There are a few One Channel to ‘n’ Items scripts, but I needed a ‘n’ Channel to ‘n’ Items – this is perfect and flexible. With my current level of experience it would’ve taken a long time to come up with the answer like this – thanks again.

(some db_connect stuff..)

$query = "SELECT * 
      FROM webref_rss_items, webref_rss_details 
      WHERE webref_rss_details.id = webref_rss_items.chan_id 
      ORDER BY webref_rss_details.id";

$t_result = mysql_query( $query ) OR die ('Could not execute query: ' . mysql_error());
$rowCount = mysql_num_rows( $t_result );
$cat = -1;  // last category
for($r = 0; $r < $rowCount; $r++)
{
        $row = mysql_fetch_array( $t_result );
        if($row['id'] != $cat)
        {
            $cat = $row['id'];

        //create doctype
        $doc = new DOMDocument('1.0','UTF-8');
        header('content-type: text/xml');

        //create rss root with values
        $root = $doc->createElement('rss');
        $root->setAttribute('version', '2.0');
        $doc->appendChild($root);

        //create channel element
        $channel = $doc->createElement("channel");
        $root->appendChild($channel);

        // add node for each record, create the text nodes for element and add text
        $title = $doc->createElement('title', $row['title']);
        $channel->appendChild($title);

        $link = $doc->createElement('link', $row['link']);
        $channel->appendChild($link);

        $desc = $doc->createElement('description', $row['description']);
        $channel->appendChild($desc);

        $lang = $doc->createElement('language', $row['lang']);
        $channel->appendChild($lang);

        $image = $doc->createElement('image');
        $image = $channel->appendChild($image);

            $imttl = $doc->createElement('title', $row['image_title']);
            $image->appendChild($imttl);

            $imlink = $doc->createElement('link', $row['image_link']);
            $image->appendChild($imlink);

            $imdesc = $doc->createElement('description', $row['image_desc']);
            $image->appendChild($imdesc);

            $imwidth = $doc->createElement('width', $row['image_width']);
            $image->appendChild($imwidth);

            $imheight = $doc->createElement('height', $row['image_height']);
            $image->appendChild($imheight);

            $imurl = $doc->createElement('url', $row['image_url']);
            $image->appendChild($imurl);

        $manEdit = $doc->createElement('managingEditor', $row['man_edit']);
        $channel->appendChild($manEdit);

        $webmaster = $doc->createElement('webmaster', $row['webmaster']);
        $channel->appendChild($webmaster);

        $copyright = $doc->createElement('copyright', $row['copyright']);
        $channel->appendChild($copyright);

        $pubDate = $doc->createElement('pubDate', $row['ch_pubDate']);
        $channel->appendChild($pubDate);

        $lastBuild = $doc->createElement('lastBuildDate', $row['lastBuild']);
        $channel->appendChild($lastBuild);

        $category = $doc->createElement('category', $row['category']);
        $channel->appendChild($category);

        $generator = $doc->createElement('generator', $row['generator']);
        $channel->appendChild($generator);

        $docs = $doc->createElement('docs', $row['docs']);
        $channel->appendChild($docs);

        $cloud = $doc->createElement('cloud', $row['cloud']);
        $channel->appendChild($cloud);

        $ttl = $doc->createElement('ttl', $row['ttl']);
        $channel->appendChild($ttl);

        $rating = $doc->createElement('rating', $row['rating']);
        $channel->appendChild($rating);

        $textInput = $doc->createElement('textInput', $row['textInput']);
        $channel->appendChild($textInput);

        $skipHours = $doc->createElement('skipHours', $row['skipHours']);
        $channel->appendChild($skipHours);

        $skipDays = $doc->createElement('skipDays', $row['skipDays']);
        $channel->appendChild($skipDays);

            }

    //Dynamically Generated Items
    $item = $doc->createElement('item');
    $item = $channel->appendChild($item);

        $it_ttl = $doc->createElement('title', $line['title']);
        $item->appendChild($it_ttl);

        $it_desc = $doc->createElement('description', $line['desc']);
        $item->appendChild($it_desc);

        $it_link = $doc->createElement('link, $line['link']');
        $item->appendChild($it_link);

        $it_guid = $doc->createElement('guid', $line['guid']);
        $item->appendChild($it_guid);

        $it_pubDt = $doc->createElement('pubDate', $line['pubDate']);
        $item->appendChild($it_pubDt);

        $it_auth = $doc->createElement('author', $line['author']);
        $item->appendChild($it_auth);

        $it_ctg = $doc->createElement('category', $line['category']);
        $item->appendChild($it_ctg);

        $it_cmnt = $doc->createElement('comments', $line['comments']);
        $item->appendChild($it_cmnt);

        $it_encl = $doc->createElement('enclosure', $line['enclosure']);
        $item->appendChild($it_encl);

        $it_src = $doc->createElement('source', $line['source']);
        $item->appendChild($it_src);



    $mast  = $row['ch_title'];
$saw = explode(" ", $mast);
$chip =  $saw[0].'-'.$saw[1]; // saw1-saw2
$beam = "../../feed/".$chip.".xml";
echo 'Wrote: ' . $doc->save($beam) . '  bytes. <br /><br />';  
}   

}
?>

Works perfectly!

Answer 1

Personally I would just go for a simple query such as

select Channel.Title, Channel.Desc, Channel.Link, Channel.id, Item.Title, Item.Desc,
Item.Link as ItemLink from Item, Channel where Channel.id = Item.Chan_id 
order by Channel.id;

as a query, get all the items (as we are talking of not a lot of items), then loop through them. Where channel.id isn’t the same as the previous channel ID, do the header thing.

I have no idea what you are doing with those sprintfs, as you are sprintf’ing nothing, they are just text strings you can put straight into the queries.

I would use classes to deal with the database, not because in this example you need it, but it is a good practice to be in, and once you get use to it it becomes second nature. however, as an example (and not necessarily as I would do it):

    $query = "select Channel.Title as ChanTitle, Channel.Desc as ChanDesc, Channel.Link, Channel.id, Item.Title, Item.Desc, Item.Link as ItemLink from Item, Channel where Channel.id = Item.Chan_id order by Channel.id";

    $t_result = mysql_query( $query ) OR die ('Could not execute query: ' . mysql_error());
    $rowCount = mysql_num_rows( $t_result );
    $cat = -1;  // last category
    for($r = 0; $r < $rowCount; $r++)
    {
        $row = mysql_fetch_array( $t_result );
        if($row['id'] != $cat)
        {
            $cat = $row['id'];
            print $row['ChanTitle']."<br>";
            print $row['ChanDesc']."<br><br>";
        }
        print $row['Title']."<br>".$row['Desc']."<br><br>";
    }

That way you are only doing the one get from the database, instead of a fetch for each small category, and just working with the data in arrays. Note this would miss out any groups that had an id without a matching channel, but I guess that would make sense.