Question

根据用户要求用户删除哪一行选择列表中选择的值和包含的文本框中的值匹配数据。例如，selected item ='city'和textbox = “波士顿”。包括一个从表中删除行的按钮。

这些是我要遵循的指示。我有两个问题，第一个问题是如果我说..选择团队名称并从表中输入一个团队我得到一个错误说：

DELETE FROM teams WHERE teamname = rockets

未找到专栏：1054未知专栏＆＃39;火箭＆＃39;在＆＃39; where子句＆＃39;

它试图使用火箭作为列名而不是需要删除的行。第二个问题是，如果我选择年份并输入正确的年份，它将删除该年份的行。如果我输入的年份不存在，我的代码表示记录已成功删除，但实际上没有删除任何内容。

我想我在这里混淆了一些事情，并且不确定它是如何为一年生工作而中途，而不是其他专栏......

HTML

<form method='post' action='phpfiles/deleteData.php'>
                    Select a column name, then enter which data to delete.
                    <br>
                    <br>
                    <label for='option1'>
                        <select name='selectColumn'>
                            <option value='teamname' id='team'>teamname</option>
                            <option value='city' id='city'>city</option>
                            <option value='bestplayer' id='best'>bestplayer</option>
                            <option value='yearformed' id='year'>year</option>
                            <option value='website' id='website'>website</option>
                        </select>
                    </label>    
                    <label for='option2'>
                        Data to delete: <input type='text' name='dataDelete'>
                    </label>
                    <br><br>
                    <input type='submit' value='Submit Delete'>
                </form>

PHP

<?php

    if ($_SERVER["REQUEST_METHOD"] == "POST"){ 

        $servername = "localhost";
        $username = "root";
        $password = "enigma";
        $dbname = "program09";
        $columnSelect = $_POST['selectColumn'];
        $deleteData = $_POST['dataDelete'];

        try {
            $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
            // set the PDO error mode to exception
            $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

            // sql to delete a record
            $sql = "DELETE FROM teams WHERE $columnSelect = $deleteData";

            // use exec() because no results are returned
            $conn->exec($sql);
            echo "Record deleted successfully";
            }
        catch(PDOException $e)
            {
            echo $sql . "<br>" . $e->getMessage();
            }

        $conn = null;
    }
?>

Answer 1

您需要单引号：

$sql = "DELETE FROM teams WHERE $columnSelect = '$deleteData'";

但最好使用预准备语句来避免SQL注入。还可以使用白名单作为列名。

$sql = "DELETE FROM teams WHERE $columnSelect = :value1";
$stmt = $conn->prepare($sql);
$stmt->execute(array(':value1'=>$deleteData));

使用php问题

1 个答案: