how to perform value calculation in mysql database using php -

i have column inside user table named paircount has value of 2 default, whenever action occur, want value minus 1 (1). wrote following code

 <?php session_start(); require_once './include/constants.php'; require_once './include/databaseconn.php'; require_once './vendor/autoload.php'; require_once './include/user.php'; require_once './include/level.php';  use \phputil\json;  $user = user::getcurrentuser();  $db = new databaseconn(); $link = $db->connect(); $sql = "update users set `payee-1` = null,  status  = ?,`paircount` = ? `payee-1` = ?"; $stmt = $link->prepare($sql);  $stmt->bind_param('sss', $status, $paircount, $payee1); $status = pair;   //here did calculation, given me error $paircount = $paircount (-1);    $payee1 = ($user->getusername()); $res = $stmt->execute();  $stmt->store_result(); if ($res) {     echo "<h1>congrate have unsubscribe pay person";     header('refresh: 3;url=icant3.php'); } else {     echo 'undone'; } 

it possible in sql query.

update users set `payee-1` = null,  status = ?, `paircount` = paircount - 1 `payee-1` = ? 

then don't need $paircount variable in php code.