PHP中的连续数组交集

Question

I am writing a file meta data app in php, and I need to search for files which have several tags. The information is stored in a mySQL table with a fileId and a tagID. The way I do this is by searching the table for the first tagId and then take the intersection of the resulting file list with consecutive SQL calls for the remaining tags:

$files = $cfiles->searchFiles($owner,$tags[0]);                                                                                     
foreach($tags as $tag){                                                           
  $temp = $cfiles->searchFiles($owner, $tag);
  $files = array_intersect($files, $temp);
}    

The problem is that array_intersect creates an associative array, ie,

$files= array("id1","id2",..."idn");

becomes

$files = array("0" => "id1", "1" => "id2", ...

when I take the intersection with itself. The problem is, that on the next iteration for the next tag, array_intersection fails because I then take the intersection between an associative array and a non-associative array. Can somebody please enlighten me?

Answer 1

So it turns out that array_intersect does not work when the entries of the arrays are arrays themselves (as they are in my case). Using array_uintersect() does the trick.