PHP MySQL row delets all in error

I've got a form with a incident issue and list of checkboxes related to users involved in the incident. The checkbox values goes into an array in the POST [userGroup].

I then need to insert all users into the involved table - works fine.

I then select all rows from the table with the incident ID and loop over them checking if they're in the array. If not - issue the SQL delete statement. The problem is that ALL rows with the incidentID ($iid) are deleted.The SQL code I'm echoing is correct though.. :(

    foreach ($_POST['userGroup'] as $val) {
        // Check if user's added already
        $sql = "SELECT userID FROM involved WHERE incidentID = $iid AND userID = $val";
        $checkSQL = mysql_query($sql) or die(mysql_error);
        $checkRows = mysql_num_rows($checkSQL); // if == 1, user is added
        if($checkRows == 0) {
            // Add user
            $sql = "INSERT INTO involved ( incidentID, userID ) VALUES ( $iid, $val )"; 
            $insertUser = mysql_query($sql);
        }
    }

    // Check if user is added but should not be
    $sql = "SELECT userID, involvedID FROM involved WHERE incidentID = $iid";
    $involvedSQL = mysql_query($sql) or die(mysql_error);
        while($row = mysql_fetch_assoc($involvedSQL)) {
            $involvedID = $row['involvedID'];
            echo "<br><br>Setting involvedID " . $involvedID . "<br>";
            $userID = $row['userID'];
            echo "Setting userID " . $userID . "<br>";
            
            if (!in_array($userID, $_POST['userGroup'])) {
                // Remove user
                echo "Could not find user " . $userID . " on involvedID " . $involvedID . "<br>";
                $delsql = "DELETE FROM involved WHERE involvedID = $involvedID";
                echo "<br>" . $delsql;
                $deleteSQL = mysql_query($delsql) or die(mysql_error);
            }
        }

Select all Open in new window