SQL Use array and use result in select(sum) statement - php

Question

I am trying to use the selected id's as an array a other statement. It seems it is not counting all the result as it is much lower that it is.. I have tried to find my answer on google but none of the options are working for me or i do not know how to use them in my case. There are no errors and i have error log on!
Here is my code, what am i doing wrong?
$counttheid = array();
$stmt3 = $mysqli->prepare("SELECT
id
FROM account
WHERE level <= '5' AND door = ? AND `group_name` = ? AND betaald = 'Yes'");
$stmt3->bind_param("ss",$usernamesession,$groupname);
$stmt3->execute();
$result3 = $stmt3->get_result(); //only works when nd_mysli is set on the server!
while ($rowid = $result3->fetch_assoc())
{
$counttheid[] = $rowid['id'];
$countid = implode(',', $counttheid);
}
$sql = "SELECT SUM(mobcash) AS totalcash FROM account WHERE id IN (?)
";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("s",$countid);
$stmt->execute();
$stmt->bind_result($row['totalcash']);
while($stmt->fetch()) $sumcash = $row['totalcash'];
//echo print_r($counttheid);
//echo implode(',', $counttheid);
echo $sumcash;
I am no profesional developer just started learning this, any help is welcome!

Answer 1

Since you have edited the question, my original answer is no longer relevant.
I suggest for you to simplify your two queries into a single query. In your first query you select a bunch of ids and in the second query you sum a different value from the same table using the ids. You can just to that in one query:
SELECT SUM(mobcash) AS totalcash
FROM account
WHERE level <= '5'
AND door = ?
AND `group_name` = ?
AND betaald = 'Yes';
Original answer
You use $result->fetch_all(MYSQLI_ASSOC), meaning each row from the result set will be an associative array with the column names as the keys and the cell values as values. That is also the case, if you only select one column.
That means for this example table
id | name | balance
----+------+---------
1 | acc1 | 12.34
2 | acc2 | 1.23
your variable $dataid will have the following value (for the simplified query SELECT id FROM account):
$dataid = [
[
"id": 1
],
[
"id": 2
]
];
To get more familiar with PHP, you could write some foreach loops yourself, but you can also use the built-in PHP function array_column (php.net: array_column):
$ids = array_column($dataids, "id");
From an SQL perspective I would also suggest for you to learn about nested queries, since you could avoid this PHP logic altogether.