Edward Kay a écrit :
-----Original Message-----
From: Fredrik Thunberg [mailto:thunis@xxxxxxxxxxxxxxxxxxx]
Sent: 04 May 2007 15:31
To: Edward Kay
Cc: php-general@xxxxxxxxxxxxx
Subject: Re: Selecting a special row from the database
Edward Kay skrev:
-----Original Message-----
From: Marcelo Wolfgang [mailto:marcelo@xxxxxxxxxxx]
Sent: 04 May 2007 14:37
To: php-general@xxxxxxxxxxxxx
Subject: Selecting a special row from the database
Hi all,
I'm building a news display page for a website, and since the
user has 2
ways to arrive there, I want to know if this is possible:
1) the user arrive at news.php
I will run a query at the db, and get the latest news to be
the main one
(full display) and display the others news in a list
2) the user arrived from a link to a specific news to news.php?id=10
It should display the news with id = 10 as the main news and get the
latest ones to display in a list of other news
I've so far was able to add a dinamic WHERE to my query ( if I have or
not the id GET parameter ) and if I don't have it, I'm able to display
the latest result as the main news, but when I have an id as a GET
parameter, I have a where clause in my query and it will
return only the
main news and not build up the news list
what I want is to separate the news that the user want to see ( the
id=XX one ) from the others rows, can someone advice me ?
Here is the code I have so far, I hope it serve as a better explanation
than mine!
<?
$newsId = $_GET['id'];
if (isset($newsID)){
$whereClause = 'WHERE auto_id ='.$newsId;
} else {
$whereClause = '';
}
mysql_connect("localhost",$user,$pass) or die (mysql_error());
mysql_select_db ($db_table);
$SQL = "SELECT * FROM tb_noticias $whereClause ORDER BY auto_id DESC";
$news_Query = mysql_query($SQL);
$recordCount = mysql_numrows($news_Query);
mysql_close();
?>
TIA
Marcelo Wolfgang
If id is set, query the DB for this news article and put as the first
element in an array. Then perform a second query WHERE ID != id
and append
the results to the array. If id isn't set, just perform the one query
without any where clause.
If you want to do it all in one query, if id is provided use
SELECT... WHERE
ID = id UNION (SELECT...WHERE ID != id ORDER BY id DESC) to get
the ordering
you want. If id isn't set just use SELECT ... ORDER BY id DESC.
I'm not sure if there would be much difference in performance as I still
think the database would perform two queries internally.
Edward
Maybe
SELECT ..., if (id = my_id,1,0) as foo
...
ORDER BY foo DESC;
Good idea! Just tried it out and it works really well.
Hello,
If you're looking for performance, why do you select everything for
articles that are not in full display ?
Isn't it better if you SELECT * just for the article you want in full
display and make another query for other titles ?
LIMIT would also help performance.
Cheers
--
Emmanuel
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