Question

I have two 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 20";
$maxpost12 =mysql_query($maxpost1);
while ($maxpost_rows = mysql_fetch_array($maxpost12 ,MYSQL_BOTH)){
$maxpost2 = $maxpost_rows[0];
}
$query = "SELECT * FROM posts WHERE id = $maxpost2";
$query2 = mysql_query($query);
return $query2;
}
$query2 = sectionposts(6);
while ($rows = mysql_fetch_array($query2)){
echo $rows['title'] . "<br/>" . "<br/>";
echo $rows['id'] . "<br/>" . "<br/>";
echo $rows['image_section'] . "<br/>";
echo $rows['subject'] . "<br/>";
echo $rows['image_post'] . "<br/>";
}

How can it take these ten results but use them in different places, and keep them arranged from one to ten.

this was the old case and i solve it but i found another 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.

    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;
?>

anyway “really” thanks again 🙂 !

Answer 1

A few thoughts regarding posted code:

• First and foremost, you should stop using mysql_ functions as they are being deprecated and are vulnerable to SQL injection.

$maxpost1 ="SELECT max(id) from posts WHERE section_id = $section_id ORDER BY ID DESC LIMIT 20";

• When you SELECT MAX, MIN, COUNT, AVG … functions that only return a single row, you do not need an ORDER BY or a LIMIT.

• Given that you are only asking for the MAX(id), you can save work by combining your queries like so:

SELECT * FROM posts 
WHERE id = (SELECT MAX(id) from posts WHERE section_id = $section_id)

If I’m understanding what you’re trying to do (please correct me if I’m wrong), your function would look something like:

function sectionposts($section_id) {
    $link = mysqli_connect("localhost", "my_user", "my_password", "world");

    $stmt = mysqli_prepare($link, "SELECT title, id, image_section, subject, image_post FROM posts " 
        . "WHERE section_id = ? ORDER BY id DESC LIMIT 10");
    mysqli_stmt_bind_param($stmt, $section_id);
    return mysqli_query($link, $stmt)
}

$result = sectionposts(6);
while ($row = mysqli_fetch_assoc($result)) {
    echo $rows['title'] . "<br /><br />";
    echo $rows['id'] . "<br /><br />";
    echo $rows['image_section'] . "<br />";
    echo $rows['subject'] . "<br />";
    echo $rows['image_post'] . "<br />";
}