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Old 01-05-2005, 06:57 AM
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Quote:
Originally Posted by cinq
Problem Number 2

I implemented a 'Previous article Next article' feature at the top of each article page which provides an easy means to quickly navigate to another article.

This is the code currently in place:
PHP Code:
# previous and next article links
$nextone $artid+1;
$chknextonequery $DB_site->query("SELECT articles_articleid FROM " TABLE_PREFIX "articles_article WHERE articles_articleid=$nextone");
if(
$DB_site->num_rows($chknextonequery)>0)
    {
        
$nextarticle 1;
    }
else
    {
        
$nextarticle 0;
    }

$previousone $artid-1;
$chkpreonequery $DB_site->query("SELECT articles_articleid FROM " TABLE_PREFIX "articles_article WHERE articles_articleid=$previousone");
if(
$DB_site->num_rows($chkpreonequery)>0)
    {
        
$prearticle 1;
    }
else
    {
        
$prearticle 0;
    } 
The template where it appears :
Code:
<span class="smallfont" style="float:$stylevar[right]">
<if condition="$prearticle==1">
<a href="articles.php?$session[sessionurl]action=viewarticle&artid=$previousone">< Previous Article</a></if>
<if condition="$nextarticle==1 && $prearticle==1">
&nbsp;&nbsp;|&nbsp;&nbsp;
</if>
<if condition="$nextarticle==1">
<a href="articles.php?$session[sessionurl]action=viewarticle&artid=$nextone">Next Article ></a></if>
</span>
Now this code works fine, BUT it assumes that all the rows in the database for articles are present in running order. eg. articleid=1,2,3,4....,100.. It presents a problem when there is a missing articleid in between. for eg. articleid=1,2,3,5,8,10,...,100...

How can I change things to make this work ?
Also if possible combine queries ?
if($next = $DB_site->query_first("SELECT whatever FROM table WHERE articles_articleid > $artid ORDER BY artid ASC"))
{
$nextarticle = 1;
}

if($previous = $DB_site->query_first("SELECT whatever FROM table WHERE articles_articleid < $artid ORDER BY artid DESC"))
{
$prearticle = 1;
}


TADA!
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