public function sellStock($stock, $quantity) { $portfolio = new table_Portfolio(); $where = "CAUS_NM_ID={$_SESSION['userid']} and COAT_TX_ID='{$stock}'"; $port = $portfolio->fetchRow($where); $qty = $port->CART_NM_Quantidade; $totalQty = $qty - $quantity; $data = array('CAUS_NM_ID' => $_SESSION['userid'], 'COAT_TX_ID' => $stock, 'CART_NM_Quantidade' => $totalQty); if ($totalQty > 0) { $portfolio->update($data, $where); } else { $portfolio->delete($where); } }