Member Avatar for weemy

i have tow tables, posts and sections, i want to get the last 10 posts WHERE section = 1,
but use the 10 results in different places, i make a function

            function sectionposts($section_id){
mysql_set_charset('utf8');
$maxpost1 ="SELECT max(id) from posts WHERE section_id = $section_id ORDER BY ID DESC LIMIT 10";
$maxpost10 =mysql_query($maxpost1);
 return($maxpost10);
    }
$query2 = sectionposts(6);
while ($rows = mysql_fetch_array($query2)){

echo $rows['title'];
echo $rows['id'];
echo $rows['image_section'];
echo $rows['subject'];
echo $rows['image_post'];

how can in take this ten results but use them with different places ,and keep them Arranged from one to ten .
Thanks...

Edited by weemy
  • 3 Contributors
  • 4 Replies
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  • 23 Hours Discussion Span
  • Latest Post Latest Post by weemy

Dani AI

Generated

Short answer: stop doing arithmetic on max(id). When rows are deleted the id sequence is not continuous, so max(id)-N can point to a non‑existent row. Fetch the last N existing rows for the section once, store them in a numerically indexed array, and reuse those array items where you need them on the page.

A compact, modern pattern (using PDO) — fetch once, then reference by index (0 = newest):

function fetchLastPosts(PDO $pdo, $sectionId, $limit = 10){
    $stmt = $pdo->prepare(
      'SELECT * FROM posts WHERE section_id = :sid ORDER BY id DESC LIMIT :lim'
    );
    $stmt->bindValue(':sid', (int)$sectionId, PDO::PARAM_INT);
    $stmt->bindValue(':lim', (int)$limit, PDO::PARAM_INT);
    $stmt->execute();
    return $stmt->fetchAll(PDO::FETCH_ASSOC); // index 0 = newest
}

$posts = fetchLastPosts($pdo, 6);
// use $posts[0], $posts[1], ... safely (check with isset/count first)

Helper to pull a rank safely:

function postByRank(array $posts, $rank){
    return $posts[$rank] ?? null; // 0-based; returns null when absent
}

Notes and tips:

  • To display oldest→newest among those 10, call array_reverse($posts).
  • If you ever need the “Nth latest” directly in SQL, use LIMIT 1 OFFSET N (but fetching 10 at once is usually cheaper than many single-row queries).
  • Never trust id arithmetic for ordinal positions. Rely on ORDER BY + LIMIT (and OFFSET when needed).
  • Migrate away from the old mysql_* functions to mysqli or PDO and use prepared statements to avoid SQL injection and compatibility problems with newer PHP versions.

was on the right track: fetch once and index the result. This approach just replaces fragile max(id)-N math with a robust, reusable array.

Recommended Answers

All 4 Replies

Member Avatar for Member #120589 
function sectionposts($section_id){
    mysql_set_charset('utf8');
    $maxpost =mysql_query("SELECT * from posts WHERE section_id = $section_id ORDER BY ID DESC LIMIT 10");
    if(mysql_num_rows($maxpost)){
        while ($rows = mysql_fetch_array($maxpost, MYSQL_NUM)){
            $output[] = $rows;
        }
    return($output);
    }
}

function formatpost($array, $rank){
    if(isset($array[$rank])){
        $r = $array[$rank];
        $output = "<h3>{$r['title']}</h3>";
        $output .= "<h4>{$r['subject']}</h4>";
        $output .= "<p>{$r['image_post']}</p>";
        $output .= "<img src='{$r['some_image']}' />";
        return $output;
    }
}


$sData = sectionposts(6);

echo formatPost($sData, 0);

...

echo formatPost($sData, 1);

...

echo formatPost($sData, 7);

You could do something like that. NOT TESTED.

Member Avatar for weemy

Nice answers and it's so helpful, but i didn't make the point well, what am i trying to do is :

1- get ten posts starts from max(id) to "$max(id)-9" form posts table.

2- using the max(id) in the top of the page and then useing $max(id)-1 in a defendant place of the page.

3- i had already generated a code

`Inline Code Example Here

    function getmax_id_with_minus ($minus){
    mysql_set_charset('utf8');
    $maxid ="SELECT max(id) FROM posts";
    $maxid1 =mysql_query($maxid);
        while ($maxid_row = mysql_fetch_array($maxid1)){
                $maxid_id = $maxid_row['0'];
                $maxid_minus = $maxid_id - $minus;
                }
    $selectedpost1 = "SELECT * FROM posts WHERE id = $maxid_minus";
    $query_selectedpost =mysql_query($selectedpost1);
        return ($query_selectedpost);

}
<?php 
$ss = getmax_id_with_minus (8);
while ($rows = mysql_fetch_assoc($ss)){
$main_post_1 = $rows;
?>

`

but i found anouther problem, that, if the client had deleted a post as id = 800 "so there aren't id = 800 in DB" so when i get the max id minus $NUM from it, and this operation must be equal id = 800, so i have a programing mistake here, how can i take care of something like that.

anyway "really" thanks again :) !

Member Avatar for Member #949455

Nice answers and it's so helpful, but i didn't make the point well,

You have to understand that Daniweb is forum where people learn things and share knowledge. What diafol gave is good but you are adding stuff now.

Member Avatar for weemy

@LastMitch
thanks for makeing this point Mr.LastMitch, i have choosed the forum site to ask and get answers because i have read alot of topics and good topics here, that what pushes me to ask here

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