Description:
------------
Environment:

MS SQL Server 2008 R2
FreeTSD 0.64_9,1

No results are returned from dblib PDO::query() + PDOStatement::fetchAll() if the same variable is re-used from a previous query/fetch.

If the variable is unset() before the second query, the behavior is as expected.

This problem is reproducible on both a fresh install of FreeBSD 9.1 and longstanding 8.2 install. This behavior was not evident on the FreeBSD 8.2 install prior to a php upgrade from 5.3.8 to 5.4.12.

Test script:
---------------
$dbh = new PDO("dblib:host=$host;dbname=$dbname", $user, $pass);

$create = $dbh->exec('DROP TABLE foo');
$create = $dbh->exec('CREATE TABLE foo (ID int PRIMARY KEY IDENTITY (1,1) NOT NULL, bar VARCHAR(10))');
$insert = $dbh->exec('INSERT INTO foo (bar) VALUES (\'baz\')');

$qry = 'select * from foo';

$stmt = $dbh->query($qry);
$results = $stmt->fetchAll(PDO::FETCH_NUM);
print_r($results);

$stmt = $dbh->query($qry);
$results = $stmt->fetchAll(PDO::FETCH_NUM);
print_r($results);

unset($stmt);
$stmt = $dbh->query($qry);
$results = $stmt->fetchAll(PDO::FETCH_NUM);
print_r($results);

Expected result:
----------------
Array
(
    [0] => Array
        (
            [0] => 1
            [1] => baz
        )

)
Array
(
)
Array
(
    [0] => Array
        (
            [0] => 1
            [1] => baz
        )

)

Actual result:
--------------
Array
(
    [0] => Array
        (
            [0] => 1
            [1] => baz
        )

)
Array
(
    [0] => Array
        (
            [0] => 1
            [1] => baz
        )

)
Array
(
    [0] => Array
        (
            [0] => 1
            [1] => baz
        )

)