Highest value number in a loop multiple times

Question

I have an INSERT loop and I need to add a reference number to it. I need all of the reference numbers in the loop to be the same. I know that with MAX() I can select the highest number in the table. But if I loop it will just increase with each loop while I need it to stay the same.

Is there a way of doing this in the query itself? Or is the only way to save it in a variable outside of the loop?

Example code:

    for($i=2;$i<=$row_count;$i++){ // Loops 3 times (example)
    $part = $vehicle.'_part'.$i;
    $description = $vehicle.'_description'.$i;
    $imageName = $vehicle.'_image'.$i;
    $parts[] = array(
        'part' => $_SESSION[$part],
        'image' => $_SESSION[$part],
        'description' => $_SESSION[$description]);
    }

    foreach($parts as $onePart){    
            $queries[] = "INSERT INTO searches_tbl (ref_nr, vozila_id, korisnici_id, part, description, image)
                        VALUES (???, (SELECT id FROM vozila_tbl ORDER BY id DESC LIMIT 1), 
                            (SELECT id FROM korisnici_tbl WHERE email = '".$email_address."' ORDER BY id DESC LIMIT 1), '".$onePart['part']."', '".$onePart['description']."', '".$onePart['image']."')";
    }

Answer 1

You can create a new table, ie searches_ref with just an AUTO_INCREMENT Primary Key-column.

CREATE TABLE searches_ref ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY );

You would then insert a new line in searches_ref before the loop, and get a new id you can use in the loop.

This way, you should not have concurrency issues (which you will probably get using MAX() )