I approach this by assigning a value to a variable and then comparing to see
if i need to write out a new title
$oldDVD = "";
while ($rows=mysql_fetch_array($result))
{
//decide whether to show the DVD title
if ($oldDVD != $rows['title'])
{
echo "<tr><td>".$rows['title']."</td></tr>";
$oldDVD = $rows['title'];
}
//echo out the rest of the data
echo "<tr><td>".$rows['comment']."</td></tr>";
}
hth
Bastien
From: "Andrew Darby" <adarby@xxxxxxxxx>
To: php-db@xxxxxxxxxxxxx
Subject: MySQL/PHP Left Join Question
Date: Thu, 25 May 2006 11:28:56 -0400
Hello, all. I don't know if this is a php-mysql question or just a
mysql, but here goes:
I have a list of DVDs that my library loans out, and I'd like to allow
people to add comments to each item. Since this list gets regenerated
periodically (it's extracted from another system, the library
catalog), there isn't a consistent ID in the dvd tables, so I'm using
the call number (which will look like DVD 2324) as the key. Anyhow, I
join the tables like this to get all the DVDs and all the comments
associated with the DVDs:
SELECT distinct dvds.title, dvds.publisher, dvds.publication_date,
dvds.call_number,
comment.id, comment.parent_id, comment.comment, comment.name
FROM dvds
LEFT JOIN comment
ON dvds.call_number=comment.parent_id
WHERE dvds.title LIKE 'A%'
ORDER BY dvds.title
With this, I'll get results like
DVD 101 A.I. This movie rocked
DVD 101 A.I. This Movie stunk
DVD 102 Adaptation . . .
DVD 103 After Hours . . .
When I loop in PHP through the records, of course, I want just the one
DVD with however many comments associated with it. Is it possible to
do this (i.e., screen out DVD dupes) in MySQL, or do I have to do it
in PHP?
If this is a dumb question, my humblest apologies, and I'd be
interested if there was a better way to handle this . . . .
Andrew
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