关于退选学程的代码，系统提示未定义变量
关于退选课程的代码，系统提示未定义变量。
退选课程提交后，系统提示错误，第15、35、38行有未定义的变量“xuehao” 请问我应该怎么修改？
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><br /><html xmlns="http://www.w3.org/1999/xhtml"><br /><head><br /><meta http-equiv="Content-Type" content="text/html; charset=gb2312" /><br /><title>退选课题</title><br /></head><br /><br /><body><br /><?php <br />//######################退选课题界面3##########################<br /> include "config.php";<br /> include "header.php";?><br /><?php<br /> extract($_POST);<br /> $query="select * from $student_table where xuehao='".$xuehao."'";<br /> mysql_query("set names 'GB2312'");<br /> $result=mysql_query($query);<br /> $row=mysql_fetch_array($result);<br /> $id=$row['id'];<br /><br /> $query1="select number as sn,surplus as ssn from $jiaoshi_table where id='$id'";<br /> mysql_query("set names 'GB2312'");<br /> $result1=mysql_query($query1);<br /> $row1=mysql_fetch_array($result1);<br /> if($row1['sn']==1)<br /> {<br /> $query2=mysql_query("update $jiaoshi_table set xuehao='未选' where id='$id'");<br /> $query3=mysql_query("update $jiaoshi_table set surplus=surplus+1 where id='$id'");<br /> }<br /> else<br /> {<br /> if(($row1['sn']-$row1['ssn'])==1)<br /> $query7=mysql_query("update $jiaoshi_table set xuehao='未选' where id='$id'");<br /> else<br /> $query6=mysql_query("update $jiaoshi_table set xuehao=replace(xuehao,concat('".$xuehao."','\n'),'') where id='$id'");<br /> $query8=mysql_query("update $jiaoshi_table set surplus=surplus+1 where id='$id'");<br /> <br /> $query5="update $student_table set id=0 where xuehao='".$xuehao."'";<br /> mysql_query("set names 'GB2312'");<br /> $result5=mysql_query($query5);<br /> if($result5==true)<br /> {<br /> echo"<p align=\"center\"><font color=\"#FF0000\"><b><big>退选课题成功！</big></b></font>";<br /> echo "<meta http-equiv=\"refresh\" content=\"2;url=back_keti.php\">";<br /> exit;<br /> }<br /> else<br /> {<br /> echo"<p align=\"center\"><font color=\"#FF0000\"><b><big>退选出错，请返回重新退选</big></b></font></p>";<br /> echo "<meta http-equiv=\"refresh\" content=\"1;url=back_keti.php\">"; <br /> exit;<br /> }<br /> }<br /><br />?><br /><?php include "foot.php";?><br /></body><br /></html>
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1664
14
1421
52
1315
25
1266
29
1239
24
MySQL's Role: Databases in Web Applications
Apr 17, 2025 am 12:23 AM
The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed.
Laravel Introduction Example
Apr 18, 2025 pm 12:45 PM
Laravel is a PHP framework for easy building of web applications. It provides a range of powerful features including: Installation: Install the Laravel CLI globally with Composer and create applications in the project directory. Routing: Define the relationship between the URL and the handler in routes/web.php. View: Create a view in resources/views to render the application's interface. Database Integration: Provides out-of-the-box integration with databases such as MySQL and uses migration to create and modify tables. Model and Controller: The model represents the database entity and the controller processes HTTP requests.
MySQL and phpMyAdmin: Core Features and Functions
Apr 22, 2025 am 12:12 AM
MySQL and phpMyAdmin are powerful database management tools. 1) MySQL is used to create databases and tables, and to execute DML and SQL queries. 2) phpMyAdmin provides an intuitive interface for database management, table structure management, data operations and user permission management.
Solve database connection problem: a practical case of using minii/db library
Apr 18, 2025 am 07:09 AM
I encountered a tricky problem when developing a small application: the need to quickly integrate a lightweight database operation library. After trying multiple libraries, I found that they either have too much functionality or are not very compatible. Eventually, I found minii/db, a simplified version based on Yii2 that solved my problem perfectly.
MySQL vs. Other Programming Languages: A Comparison
Apr 19, 2025 am 12:22 AM
Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.
Laravel framework installation method
Apr 18, 2025 pm 12:54 PM
Article summary: This article provides detailed step-by-step instructions to guide readers on how to easily install the Laravel framework. Laravel is a powerful PHP framework that speeds up the development process of web applications. This tutorial covers the installation process from system requirements to configuring databases and setting up routing. By following these steps, readers can quickly and efficiently lay a solid foundation for their Laravel project.
MySQL for Beginners: Getting Started with Database Management
Apr 18, 2025 am 12:10 AM
The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA
Solve MySQL mode problem: The experience of using the TheliaMySQLModesChecker module
Apr 18, 2025 am 08:42 AM
When developing an e-commerce website using Thelia, I encountered a tricky problem: MySQL mode is not set properly, causing some features to not function properly. After some exploration, I found a module called TheliaMySQLModesChecker, which is able to automatically fix the MySQL pattern required by Thelia, completely solving my troubles.
