MySQL: Multiple Photos and Videos for News with Joins - php

Question

I want multiple photos and multiple videos, the main problem is that I can't get them inline if I don't use joins.
So for example, I get 2 photos a video and again a photo.
I have a parent news table and 2 secondary table news_photos and news_videos and I want to get in one query the photos and videos for the news.
Is this somehow possible?
mysql_query("
SELECT *
FROM news_photos, news_videos
FULL JOIN news_videos
ON news_id = {$news_id}
FULL JOIN news_photos
ON news_id = {$news_id}
");
An image about the structure:

Answer 1

There's actually only a single FULL JOIN in that, since you are not involving the news table at all.
SELECT *
FROM news_photos
FULL JOIN news_videos
ON news_photos.news_id=news_videos.news_id
WHERE news_photos.news_id=... OR news_videos.news_id=...
FULL JOIN is not supported by MySQL. It can be less-efficiently simulated using two LEFT JOINs and a UNION, but it's relatively rare that you actually need to. Assuming every photo and video does belong to a news, you could avoid it and get a more conventional query by bringing the news table into it:
SELECT *
FROM news
LEFT JOIN news_photos ON news_photos.news_id=news.id
LEFT JOIN news_videos ON news_videos.news_id=news.id
WHERE news_id=...
But still, this is almost certainly not what you mean! If there are multiple photos and videos for a news item, you would be effectively creating a cartesian product, where every combination of photo and video produces a row. This is the sort of combinatorial explosion you almost never want!
If you just want one of each photo and video, I suppose you could hack that into a single query using a LEFT JOIN that will always give NULL on the other side:
SELECT * FROM news_photos
LEFT JOIN news_videos ON 0
WHERE news_photos.news_id=...
UNION SELECT * FROM news_photos
RIGHT JOIN news_videos ON 0
WHERE news_videos.news_id=...
But there's really nothing to be gained by this. Don't shoehorn two separate queries (“I'd like the photos for a news, and the videos for a news”) into one. Just do it the trivial way:
SELECT * FROM news_photos
WHERE news_id=...
SELECT * FROM news_videos
WHERE news_id=...

Answer 2

i would do it using a stored procedure that had multiple select statements as follows:
http://pastie.org/1141100
drop procedure if exists list_news_photos_videos;
delimiter #
create procedure list_news_photos_videos
(
in p_news_id int unsigned
)
proc_main:begin
select n.* from news n where n.news_id = p_news_id;
select p.* from news_photos p where p.news_id = p_news_id order by photo_id desc;
select v.* from news_videos v where v.news_id = p_news_id order by video_id desc;
end proc_main #
you would call this in mysql as follows:
call list_news_photos_videos(2);
then you can call the stored procedure from php (1 db call only) using mysqli as follows:
http://pastie.org/1141103
<?php
// quick and dirty demo - needs to be made more robust !!
$db = new Mysqli("localhost", "foo_dbo", "pass", "foo_db");
$sql = sprintf("call list_news_photos_videos(%d)", 2); // get all the news related data in one query
$result = $db->query($sql);
//news item
$row = $result->fetch_assoc();
echo sprintf("<h2>news item</h2>news_id = %d subject = %s <br/>", $row["news_id"], $row["subject"]);
$result->free();
//news photos
$db->next_result();
$result = $db->use_result();
echo "<h2>news photos</h2>";
while ($row = $result->fetch_assoc()){
echo sprintf("photo_id = %d subject = %s<br/>", $row["photo_id"], $row["subject"]);
}
$result->free();
//news videos
$db->next_result();
$result = $db->use_result();
echo "<h2>news videos</h2>";
while ($row = $result->fetch_assoc()){
echo sprintf("video_id = %d subject = %s<br/>", $row["video_id"], $row["subject"]);
}
$result->free();
$db->close();
?>