PHP在MYSQL數據庫中插入兩個重複行

Question

我遇到了PHP和MYSQL的問題。我有一個HTML表單，它在提交時運行以下PHP腳本。問題是以下PHP代碼將數據插入數據庫兩次。我認爲這是值得做下面的PHP，而不是數據庫：在你的代碼

<?php 

$first_name = $_POST['firstname']; 
$last_name = $_POST['lastname']; 
$display_name = $_POST['displayname']; 
$email = $_POST['email']; 
$password = $_POST['password']; 
$add_line1 = $_POST['addline1']; 
$add_line2 = $_POST['addline2']; 
$city = $_POST['city']; 
$county = $_POST['county']; 
$postcode = $_POST['postcode']; 

$sql = "INSERT INTO members (memberID, 
memberPassword, 
memberFirstName, 
memberLastName, 
memberAddressLine1, 
memberAddressLine2, 
memberCity, 
memberCounty, 
memberPostcode, 
memberDisplayName) 
VALUES ('$email', 
'$password', '$first_name', '$last_name', 
'$add_line1', '$add_line2','$city', 
'$county', '$postcode', '$display_name')"; 

if (!mysqli_query($conn,$sql)) 
{ 
    die('Error: ' . mysqli_error($conn)); 
} 
mysqli_query($conn,$sql); 
echo 'Guest Added'; 
mysqli_close($conn); 

?> 

Answer 1

if (!mysqli_query($conn,$sql)) 
{ 
    die('Error: ' . mysqli_error($conn)); 
} 
mysqli_query($conn,$sql); 

你有mysqli_query($conn,$sql);兩次。一旦進入if（），並且一次在外面。其中每個將插入到您的數據庫。

這裏要注意的一點是，if中的mysqli_query被評估 - 也就是說，它被運行並且if語句對函數調用的結果執行。因此，您不需要再次調用它。

Answer 2

圖莎爾指出了雙mysqli的查詢，他是對的，除此之外，該代碼是現在將導致你安全隱患，因爲它允許SQL注入......

請修改您的代碼如下：

$first_name = mysqli_escape_string($conn, $_POST['firstname']); 
$last_name = mysqli_escape_string($conn, $_POST['lastname']); 
$display_name = mysqli_escape_string($conn, $_POST['displayname']); 
$email  = mysqli_escape_string($conn, $_POST['email']); 
$password  = mysqli_escape_string($conn, $_POST['password']); 
$add_line1 = mysqli_escape_string($conn, $_POST['addline1']); 
$add_line2 = mysqli_escape_string($conn, $_POST['addline2']); 
$city   = mysqli_escape_string($conn, $_POST['city']); 
$county  = mysqli_escape_string($conn, $_POST['county']); 
$postcode  = mysqli_escape_string($conn, $_POST['postcode']);