我希望我的表为创建的每个组自动增加一个groupid。这些组是从userinformation表中随机创建的。组信息表将随机组id（从userinformation表中选择）存储到其表中。到目前为止，我已经能够增加它。我只得到零

$GroupSize = $_POST['groupsize'];

//Connect to the Server+Select DB
$con = mysqli_connect($host, $user, $password, $dbName) or die("Nope");

if (isset($_POST['create'])) {

//assign group id to groups created
//insert groupinformation to table from userInformation

//What I Have Tried
     //$query = "INSERT INTO groupInformation SELECT RegistrationId FROM (Select RegistrationId from userInformation order by RAND() LIMIT ".$GroupSize.")";
    //$query = "INSERT INTO groupInformation(RegistrationId) SELECT RegistrationId FROM (Select * from userInformation order by RAND() LIMIT ".$GroupSize.") AS j";

    $query = "INSERT INTO groupInformation(RandomGroupId,RegistrationId) SELECT randomRegistrationId,RegistrationId FROM (Select *,RAND() AS randomRegistrationId FROM userInformation ORDER BY randomRegistrationId LIMIT ".$GroupSize." ) AS j";
    $result = mysqli_query($con, $query) or die ("query failed " . mysqli_error($con));

}

mysqli_close($con);

这是我的table：


这是我的电流输出：

我需要组有random groupid来递增，比如（1004 1003 1000）=1（randomgroupid），（1004 1002，1000）=2（randomgroupid）。。。