Is it possible to keep unique index in result array using PHP PDO::FETCH_UNIQUE?

Question

I'm using the following PDO statement with the PDO::FETCH_UNIQUE flag to make the result array indexed by the unique row ID.

<?php
    $statement = $conn->prepare("
        SELECT
            unique_id, field_1, field_2, field_3
        FROM
            table
        WHERE
                field_1 = 'foo'
            AND field_2 = ?
        ORDER BY
            field_3
    ");

    if($statement->execute(array($field_2_value)))
    {
        $resultArray = $statement->fetchAll(PDO::FETCH_ASSOC|PDO::FETCH_UNIQUE);
    }
?>

$resultArray:

Array
(
    [123] => Array
        (
            [field_1] => foo
            [field_2] => someVal
            [field_3] => bar
        )
    [234] => Array
        (
            [field_1] => foo
            [field_2] => someVal
            [field_3] => car
        )
    [345] => Array
        (
            [field_1] => foo
            [field_2] => someVal
            [field_3] => dog
        )
)

Is there a way to keep both the array indexes as they are and retain the unique row ID in the row data like this:

 Array
(
    [123] => Array
        (
            [unique_id] => 123
            [field_1] => foo
            [field_2] => someVal
            [field_3] => bar
        )
    [234] => Array
        (
            [unique_id] => 234
            [field_1] => foo
            [field_2] => someVal
            [field_3] => car
        )
    [345] => Array
        (
            [unique_id] => 345
            [field_1] => foo
            [field_2] => someVal
            [field_3] => dog
        )
)

I realise I could do this with a secondary loop but it would feel a lot cleaner if this was an option in fetchAll().

Answer 1

Yes, it perfectly possible, as you can always add an extra field to the field list.

$statement = $conn->prepare("
    SELECT
        unique_id uid, unique_id, field_1, field_2, field_3
    FROM
        table
    WHERE
            field_1 = 'foo'
        AND field_2 = ?
    ORDER BY
        field_3
");

and have your unique_id among values.

However, I don't think it's quite necessary as you can always get an index from foreach as it mentioned in the other answer.