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

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 when I do this in Doctrine and execute:

$em->createQuery("SELECT a.id FROM Auction a")->getScalarResult();

I get an array like this:

array(
    array('id' => 1),
    array('id' => 2),
)

Instead, i'd like to get an array like this:

array(
    1,
    2
)

How can I do that using Doctrine?

Solution 1:

You can use array_map, and since you only have on item per array, you can elegantly use 'current' as callback, instead of writing a closure.

$result = $em->createQuery("SELECT a.id FROM Auction a")->getScalarResult();
$ids = array_map('current', $result);

See Petr Sobotka's answer below for additional info regarding memory usage.

As jcbwlkr's answered below, the recommended way it to use array_column.

As of PHP 5.5 you can use array_column to solve this

$result = $em->createQuery("SELECT a.id FROM Auction a")->getScalarResult();
$ids = array_column($result, "id");