Update numbers in table with variable and update variable

Update numbers in table with variable and update variable

As you can see from the table below the user with the id of 1 has 10
points altogether
What I'm trying to do is have one number submitted from a form
$edit_points to loop through and subtract from user 1
This number could be anything eg:
$edit_points = 6
would subtract 4 from the first record
then move to the next and only subtract the remainder 2
then break out of loop
UserID | TotalPoints
-------------------
1 | 4
1 | 4
1 | 2
4 | 3
3 | 3
5 | 4
This is what I've got so far
$pointLeft = $edit_points;//sent from form
while($point = mysqli_fetch_array($output)){
if($pointLeft > $point["TotalPoints"]){//if pointsLeft more than this record
$remainder = $pointLeft-$point["TotalPoints"];//get remainder
$query2 = "UPDATE pointstable SET TotalPoints=0 WHERE UserID=".$UserID;
$output2 = $mysqli->query($query2);
}elseif($pointLeft < $point["TotalPoints"]){
$remainder = $point["TotalPoints"] - $pointLeft;
$query2 = "UPDATE pointstable SET TotalPoints=".$remainder." WHERE
UserID=".$UserID;
$output2 = $mysqli->query($query2);
}
$pointLeft = $remainder;
}
It works to a point and seems to populate all the records with the same
last value that remainder holds I've tried break and putting an if
($pointLeft<=0) above the first if
but none works.
any help? or a better way of doing it preferably using php