Question

代码1完美无缺，并更新了考勤表：

<?php 
$date = $_POST['date'];
$subject = $_POST['subject'];
$con=mysqli_connect("localhost","root","","notifier");
if (mysqli_connect_errno())
{
    echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

$result = mysqli_query($con,"SELECT * FROM student");

echo "Enter the attendance. Please untick for 'ABSENT' students and submit";
echo "<br>";
echo "<form action=\"d.php\" method=\"post\">";
while($row = mysqli_fetch_array($result))
{
    echo "<br>" .$row['classrollno'] . "&nbsp&nbsp;&nbsp<input type=\"checkbox\" name=\"p[]\" value=\"" . $row['studentid'] . "\" checked>";

    $sql="INSERT INTO attendance (rollno, subjectid, date)
    VALUES
    ('{$row['classrollno']}','$_POST[subject]','$_POST[date]')";

    if (!mysqli_query($con,$sql))
    {
      die('Error: ' . mysqli_error($con));
    }
}
mysqli_close($con);
echo "<input type=\"hidden\" name=\"date\" value=\"" . $date . "\">";
echo "<input type=\"hidden\" name=\"subject\" value=\"" . $subject . "\">";
    echo "<input type=\"submit\" name=\"submit\" value=\"submit\">";
echo "</form>";
?>

代码二给出错误，应根据从上一页收到的复选框更新表：

<?php
$con=mysqli_connect("localhost","root","","notifier");
if (mysqli_connect_errno())
{
    echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

foreach($_POST['p'] as $value)
{
$sql="UPDATE attendance SET presenty='P'
WHERE studentid='{$value}' AND subjectid='$_POST[subject]' AND date='$_POST[date]')";

    if (!mysqli_query($con,$sql))
    {
      die('Error: ' . mysqli_error($con));
    }
}
mysqli_close($con);
?>

错误：您的SQL语法出错;查看与您的MySQL服务器版本对应的手册，以获得正确的语法，以便在附近使用＆＃39;）＆＃39;在第2行

但这行在以前的文件中完全正常。

Answer 1

Line 1: UPDATE attendance SET presenty='P'
Line 2: WHERE studentid='foo' AND subjectid='bar' AND date='baz')

错误：......在第2行附近'）'

第2行的唯一)是结束的{{1}}。删除它。

+

You need braces around $_POST[stuff].

Answer 2

你缺少大括号

$sql="UPDATE attendance SET presenty='P'
WHERE studentid='{$value}' AND subjectid='$_POST[subject]' AND date='$_POST[date]')";

必须是

$sql="UPDATE attendance SET presenty='P'
WHERE studentid='{$value}' AND subjectid='{$_POST[subject]}' AND date='{$_POST[date]}'";
//                                        ^               ^            ^            ^

警告：您的代码很容易被SQL注入。请尝试使用预准备语句或至少验证并正确转义$_POST变量

编辑： Yuor第一个代码也有类似的问题

('{$row['classrollno']}','$_POST[subject]','$_POST[date]')";

应该是

('{$row['classrollno']}','{$_POST[subject]}','{$_POST[date]}')";

参考：PHP Strings Manual

如何解决这个mysqli错误

2 个答案: