PHP sqlsrv query to database

First if I'm not wrong you are storing sqlsrv_connect result into $conn and this result isn't a class obj its a resource, so remove $db->conn

This example, will connect, then fetch if there are resources returned from sqlsrv_query

$conn_array = array (
    "UID" => "sa",
    "PWD" => "root",
    "Database" => "nih_bw",
);
$conn = sqlsrv_connect('BILAL', $conn_array);
if ($conn){
    echo "connected";
    if(($result = sqlsrv_query($conn,"SELECT * FROM routines")) !== false){
        while( $obj = sqlsrv_fetch_object( $result )) {
              echo $obj->colName.'<br />';
        }
    }
}else{
    die(print_r(sqlsrv_errors(), true));
}

After you've successfully executed the query with sqlsrv_query you can fetch the results, e.g., by using sqlsrv_fetch_array:

$result = sqlsrv_query($db->db_conn, "SELECT * FROM routines");
if($result === false) {
    die( print_r( sqlsrv_errors(), true) );
}

while( $row = sqlsrv_fetch_array($result, SQLSRV_FETCH_ASSOC) ) {
    echo $row['column1'].", ".$row['column2']."<br />";
}