這是我的代碼鎖定表之後,我得到警告
$ar = ($_POST['ar']);
$query = "lock table stock write";
$res = mysqli_query ($db, $query);
/*******Count******/
$query = "SELECT SUM(quantita_vendita) AS somma FROM stock";
$res = mysqli_query ($db, $query);
$row = mysqli_fetch_array($res);
$somma = $row['somma'];
if($ar<=$somma){
$query = "SELECT * FROM user, info WHERE info.id_user = user.id and user.email = '{$_SESSION['email']}'";
$res = mysqli_query ($db, $query);
if(mysqli_num_rows($res) > 0) {
$row = mysqli_fetch_assoc($res);
$azioni = $row['azioni'];
$denaro = $row['denaro'];
$id = $row['id'];
mysqli_free_result($res);
}
如果不插入鎖,它的工作原理。 相反當我插入鎖時,我有一個警告(mysqli_num_rows()預計參數1被mysqli_result,布爾中給出..)爲if(mysqli_num_rows($res) > 0)
解決,謝謝! – Peppifg