How to get a one-dimensional scalar array as a doctrine dql query result?

Question

I want to get an array of values from the id column of the Auction table. If this was a raw SQL I would write:

SELECT id FROM auction

But w

Answer 1

Ascarius' answer is elegant, but beware of memory usage! array_map() creates a copy of passed array and effectively doubles memory usage. If you work with hundreds of thousands of array items this can become an issue. Since PHP 5.4 call-time pass by reference has been removed so you cannot do

// note the ampersand
$ids = array_map('current', &$result);

In that case you can go with obvious

$ids = array();
foreach($result as $item) {
  $ids[] = $item['id'];
}