Question

I currently have a table that holds among other things:

ID | pagetitle | parent
1  |  Page 1   |   0
2  |  Page 2   |   1
3  |  Page 3   |   2

I am trying to select all the pages, along with their parent’s pagetitle.

Currently I am looping through the results in PHP, grabbing the pagetitles for those pages with parents, and it looks pretty ugly:

function showPageParent($pageid) {
    do {
        $result = mysql_query("SELECT parent FROM pages WHERE id=" . qt($pageid));
        while($row = mysql_fetch_array($result)) {
            $crumbs[] = $row['parent'];
            $pageid1 = $row['parent'];
        }
    } while($pageid1!=0);
    sort($crumbs);
    foreach($crumbs as $crumb) {
        $result = mysql_query("SELECT id,pagetitle FROM pages WHERE id=" . $crumb);
        while($row = mysql_fetch_array($result)) {
            $out .= $row['pagetitle'] . " > ";
        }
    }
    if(count($crumbs) < 2) {
        return showPageTitle($pageid);
    } else {
        return $out;
    }
}

It works, but it is very old code, I am in the processes of re-writing a LOT of this sytem, and would love to pretty this thing up with one call to the database to return something like this:

ID | pagetitle | parent-pagetitle

Is this possible using inner selects?

edit

I’d like to point out, I am not the original author of the PHP, I am aware it’s poorly written :p

Answer 1

select p.id
     , p.title
     , pp.id
     , pp.title parentitle
  from pages p
  left
 outer
  join pages pp
    on p.parent = pp.id

You can add another join for each level of depth, if needed.