传递数组并检查值

Question

While creating a group with user ids, I am checking if the entered id exists in database. If it exists, group should be created, if not it should pop out an error.

I am passing array with user ids to a function user_check, but it is not getting checked. Here is my code:

<?php

    function user_check($user_id)
    {
        $u1 = mysqli_query($con, "SELECT uid from users where uid<>'" . $_SESSION['user_id'] . "'");
        while ($row = mysqli_fetch_array($u1)) {
            $users = $row['uid'];
            echo "users" . $users;
            $users1 = sort($users);
            $users2 = sort($user_id);
            printf($users1);
            if ($user1 == $user2) {
                echo "same";
            } else {
                echo "not same";
            }
        }
    }

Answer 1

Given a list of user_ids (that you have validated/filtered already) you could write a function something like the following (untested):

function all_users_exist(array $user_ids, Mysqli $con)
{
    $result_uids = [];
    $ids         = implode(',', $user_ids);
    $sql         = "SELECT uid from users WHERE uid IN ($ids)";
    $result      = $con->query($sql);
    if($result)
        while ($row = $result->fetch_array(MYSQLI_ASSOC))
            $result_uids[] = $row['uid'];
    sort($user_ids);
    sort($result_uids);

    return $user_ids == $result_uids;
}