SQL Delete语句不起作用

Question

include_once 'dbfunction.php';
getDbConnect();

mysqli_query("DELETE FROM crewlist WHERE id = $_GET[crew_id]") or die (mysqli_error());
echo 'Delete success';
header ('Location: crewlisting.php');

此代码不起作用，但是当我通过硬编码将crew_id替换为实际主键时，删除功能正常工作

Answer 1

使用此（MySQLi Procedural）

dbfunction.php应该是

<?php
    $servername = "localhost";
    $username = "username";
    $password = "password";
    $dbname = "myDB";

    // Create connection
    $conn = mysqli_connect($servername, $username, $password, $dbname);
    // Check connection
    if (!$conn)
    {
        die("Connection failed: " . mysqli_connect_error());
    }
?>

并且插入页面应为

<?
    include ("dbfunction.php"); //include db connection

    $id = $_REQUEST['crew_id'];
    $sql = "DELETE FROM crewlist WHERE id = '$id' ";

    if (mysqli_query($conn, $sql))
    {
        echo "Record deleted successfully";
    }
    else
    {
        echo "Error deleting record: " . mysqli_error($conn);
    }

    mysqli_close($conn);

?>

错误是

1. getDbConnect()
中没有定义任何功能

2. 如果您对'和"感到困惑，请将功能拆分

   $id = $_REQUEST['crew_id'];
   $sql = "DELETE FROM crewlist WHERE id = '$id' ";
   

3. 以正确的格式使用mysqli_query和mysqli_error

4. 和mysqli_query中的错误，您没有将连接传递给MySQLi
5. 当数据库部件完成时，关闭连接mysqli_close($conn);

Answer 2

更正您的查询：

mysqli_query("DELETE FROM crewlist WHERE id ='".$_GET['crew_id']."'") or die('Error: ' . mysqli_error());