How to Prevent While Loop from Affecting Last DB Result

[sandbox]

Hi everyone,

 

Okay, so I'm using the following code to extract my navigation pages from a DB and display them in the footer of the page. My aim is to add an " | " between each link which I have achieved, but as it stands, it also adds an " | " after the last result which is not the affect I'm looking for. Does anybody know a way in which to prevent this?

 

Thanks for taking the time to help.

 

 

<?php
    $sql = "SELECT *
	    FROM `navigation`
	    ORDER BY position ASC";
							
    $qry = mysql_query($sql);
							
    confirm_query($qry);
							
    while ($res = mysql_fetch_array($qry)) {
									
    echo "<a href=\"{$res['url']}\">" . $res['page'] . "</a>";
    echo " | ";
    }
?>

 

[Psycho]

There are two (well, three actuall) methods I can think of:

 

1. Don't echo the values to the page directly. Instead append the text to a variable. Then when the loop completes, use substr() to remove the last three characters from the variable before echoing to the page.

 

2. Create the code for the individual links as elements in an array - then implode the results using the delimiter of " | ".

 

3. The third solution is to use GROUP_CONCAT in the query to return the results as a single concatenated value. But, you would also have to use string functions to have the query automatically generate the HTML code. That's possible, but it's not a good idea to hard-code presentation logic into your DB queries. So, while this is possible, probably not a good idea.

 

I prefer #2

<?php
    $sql = "SELECT *
        FROM `navigation`
        ORDER BY position ASC";
    $qry = mysql_query($sql);

    confirm_query($qry);

    $links = array();
    while ($res = mysql_fetch_array($qry))
    {
        $links[] = "<a href=\"{$res['url']}\">{$res['page']}</a>";
    }

    echo implode(" | ", $links);
?>
 

Edited April 15, 2013 by Psycho

[sandbox]

@Psycho - Thank you very much for the quick and helpful response/resolutions to my problem. I would have to agree, #2 seems like the best option of the 3 so I will go ahead with that one. Thanks once again for your time.

[lemmin]

I've actually done efficiency testing on this and #1 is the most efficient. The difference is negligible to a fairly large number of loops, so personal choice weighs more for most situations.

 

Also, it is helpful to know (if you didn't) that a negative value can be passed as the length for substr():

$sql = "SELECT *
	FROM `navigation`
	ORDER BY position ASC";
					
$qry = mysql_query($sql);
					
confirm_query($qry);
		
$out = '';
while ($res = mysql_fetch_array($qry)) {					
	$out .= "<a href=\"{$res['url']}\">" . $res['page'] . "</a> | ";
}
echo substr($out, 0, -3);

Edited April 15, 2013 by lemmin