PHP Fatal error: Call to a member function query() on resource ... on line 17.

<?php
$DB = '//DBGOESHERE:PORT/SIDHERE';
$DB_USER = '****';
$DB_PASS = '****';

$conn = oci_connect($DB_USER, $DB_PASS, $DB);

//check for errors
if (!$conn)
{
    $e = oci_error();
    print htmlentities($e['message']);
    exit;
}

$sql = "select display_name, last_export_file, last_export_date from schema.ms_export where last_export_date > sysdate -1 order by last_export_date desc";
$stid = oci_parse($conn, $sql);
oci_execute($stid);
while (oci_fetch($stid)) {
    echo oci_result($stid, 'display_name') . " | ";
    echo oci_result($stid, 'last_export_file') . " | ";
    echo oci_result($stid, 'last_export_date') . "<br>n";
}
oci_free_statement($stid);
oci_close($conn);
?>