sp php发送参数mysqli

Question

我想通过我发送的php mysql sp参数。 这是我的代码

function sendSpId()
{
    global $id;
    global $connection;
    $sql = "CALL `sp_st_SelectUserAll`($id)";
    $result = mysqli_query($connection, $sql);
    if ($result === FALSE) {
        die(mysqli_error($connection)); // TODO: better error handling
    }
    //loop the result set
    return mysqli_fetch_array($result);

}

这是我的连接

<?php
 $serverName = "localhost";
 $userName = "root";
 $pass = "";
 $dbName = "univercity";

 $connection = mysqli_connect($serverName, $userName, $pass, $dbName);
 mysqli_set_charset($connection, "utf8");
 if ( !$connection ) {
    die( 'connect error: '.mysqli_connect_error() );
 }


?>

这是我的sp

BEGIN
SELECT * FROM `students` WHERE `id`= id;
END

变量$ id由会话

接收

$id = $_SESSION['id'];

但是当我运行项目时，我得到以下错误

Commands out of sync; you can't run this command now

谢谢