MySQL不删除记录 [英] MySQL not deleting records

问题描述

我正在尝试获取一种表格来删除表中的行，但是除了行删除之外，我已完成所有工作.它清除表中的所有值，但不删除行或ID.我已经尝试提交了

I am trying to get a form to delete rows in a table, but I am getting everything done but the row deletion. It clears all value in the table but it does not delete the row or ID. I have tried committing it

PHP脚本

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
// Setting up the Database Connection
$servername = "localhost";
$username = "root";
$password = "Fh3dSWIWCLd4";
$dbname = "servers";
$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
//Capturing the POST Data
$id = $_POST['id'];

$sql = "DELETE FROM sv_info WHERE id='$id' LIMIT 1";

// Executing the SQL statement
if ($conn->query($sql) === TRUE) {
header("Location:http://osgaming.joec.pw/login/");
} else {
echo "Error: " . $sql . "
" . $conn->error;
}
// Closing the database connection
$conn->close();
}
?>

HTMLform

<?php include 'sql-dbsv-del.php'; ?>
<h2><b class="e">Delete Entries</b></h2> 
<form action="<?php echo $_SERVER['PHP_SELF'] ?>" method="post" class="form-group">
<label for="id">Database ID</label>
<input type="number" name="id" class="form-control" placeholder="Database ID"><br />
<input type="submit" value="Delete Entry" class="btn btn-danger">
</form>

https://gyazo.com/ca3f10f862b3993f5d716cb49242304b 它对数据库中的变量有什么作用

https://gyazo.com/ca3f10f862b3993f5d716cb49242304b There is an image to what it is doing to the variable in the database

推荐答案

了解基本的PHP字符串语法:

Learn basic PHP string syntax:

$sql = "DELETE FROM sv_info WHERE id='.$id.' LIMIT 1";
       ^--start of PHP string                       ^---end of PHP string

您正在生成文字查询字符串

You're generating the literal query string

DELETE FROM sv_info WHERE id='.4.' LIMIT 1

请注意，您对PHP字符串串联的错误尝试实际上是如何成为查询字符串的一部分.您已经 IN 一个php字符串，因此您无法在该字符串中执行PHP-PHP不可递归嵌入/执行.

Note how your bad attempt at PHP string concatenation actually became part of the query string. you're already IN a php string, so you can't execute PHP inside that string - PHP is not recursively embeddable/executable.

其中任何一种都可以工作:

Either of these would work:

$sql = "DELETE FROM sv_info WHERE id='$id' LIMIT 1";
$sql = "DELETE FROM sv_info WHERE id='" . $id . "' LIMIT 1";

但是，当然，仍然会让您容易受到 sql注入攻击.

but of course, still leave you vulnerable to sql injection attacks.

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