Php crud删除所有行

我正在尝试使用crud删除数据库中的所有行，这是我的删除响应页面。 我尝试了查询delete*，但没有成功，所以我手动键入了如下内容。这些值将作为未识别的索引出现。有谁能帮忙，告诉我我做错了什么，或者给我一个更简单的方法吗

<?php 
include "library.php"; 
include "database.php";
?>


<?php
//Get data from form
$faculty=$_POST["faculty"];
$date=$_POST["date"];
$modulecode=$_POST["modulecode"];
$moduletitle=$_POST["moduletitle"];
$school=$_POST["school"];
$modulebookcontent=$_POST["modulebookcontent"];
$moduleorganisation=$_POST["moduleorganisation"];
$lrcmaterials=$_POST["lrcmaterials"];
$moduledifficulty=$_POST["moduledifficulty"];
$modulesimilarity=$_POST["modulesimilarity"];
$contentinteresting=$_POST["contentinteresting"];
$previousknowledge=$_POST["previousknowledge"];
$understoodassessmentrequirements=$_POST["understoodassessmentrequirements"];
$assessmentmethod=$_POST["assessmentmethod"];
$markedwork=$_POST["markedwork"];
$ML_interestforsubject=$_POST["ML_interestforsubject"];
$ML_contentclear=$_POST["ML_contentclear"];
$ML_appropriateteachingpace=$_POST["ML_appropriateteachingpace"];
$ML_reachableforadvice=$_POST["ML_reachableforadvice"];
$ML_helpfulfeedback=$_POST["ML_helpfulfeedback"];
$L1_interestforsubject=$_POST["L1_interestforsubject"];
$L1_contentclear=$_POST["L1_contentclear"];
$L1_appropriateteachingpace=$_POST["L1_appropriateteachingpace"];
$L1_reachableforadvice=$_POST["L1_reachableforadvice"];
$L1_helpfulfeedback=$_POST["L1_helpfulfeedback"];
$L2_interestforsubject=$_POST["L2_interestforsubject"];
$L2_contentclear=$_POST["L2_contentclear"];
$L2_appropriateteachingpace=$_POST["L2_appropriateteachingpace"];
$L2_reachableforadvice=$_POST["L2_reachableforadvice"];
$L2_helpfulfeedback=$_POST["L2_helpfulfeedback"];
$moduleleader=$_POST["moduleleader"];
$lecturer1=$_POST["lecturer1"];
$lecturer2=$_POST["lecturer2"];
$indpstudy=$_POST["indpstudy"];
$attendance=$_POST["attendance"];
$bestfeatures=$_POST["bestfeatures"];
$improvemodule=$_POST["improvemodule"];


$queryString = "delete from studentanswers where faculty=".$faculty; 
$queryString = "delete from studentanswers where date=".$date; 
$queryString = "delete from studentanswers where modulecode=".$modulecode; 
$queryString = "delete from studentanswers where moduletitle=".$moduletitle;
$queryString = "delete from studentanswers where school=".$school; 
$queryString = "delete from studentanswers where modulebookcontent=".$modulebookcontent; 
$queryString = "delete from studentanswers where moduleorganisation=".$moduleorganisation; 
$queryString = "delete from studentanswers where lrcmaterials=".$lrcmaterials; 
$queryString = "delete from studentanswers where moduledifficulty=".$moduledifficulty; 
$queryString = "delete from studentanswers where modulesimilarity=".$modulesimilarity; 
$queryString = "delete from studentanswers where contentinteresting=".$contentinteresting; 
$queryString = "delete from studentanswers where previousknowledge=".$previousknowledge; 
$queryString = "delete from studentanswers where understoodassessmentrequirements=".$understoodassessmentrequirements; 
$queryString = "delete from studentanswers where assessmentmethod=".$assessmentmethod; 
$queryString = "delete from studentanswers where markedwork=".$markedwork; 
$queryString = "delete from studentanswers where ML_interestforsubject=".$ML_interestforsubject;
$queryString = "delete from studentanswers where ML_contentclear=".$ML_contentclear; 
$queryString = "delete from studentanswers where ML_appropriateteachingpace=".$ML_appropriateteachingpace; 
$queryString = "delete from studentanswers where ML_reachableforadvice=".$ML_reachableforadvice;
$queryString = "delete from studentanswers where ML_helpfulfeedback=".$ML_helpfulfeedback; 
$queryString = "delete from studentanswers where L1_interestforsubject=".$L1_interestforsubject; 
$queryString = "delete from studentanswers where L1_contentclear=".$L1_contentclear;
$queryString = "delete from studentanswers where L1_appropriateteachingpace=".$L1_appropriateteachingpace; 
$queryString = "delete from studentanswers where L1_reachableforadvice=".$L1_reachableforadvice; 
$queryString = "delete from studentanswers where L1_helpfulfeedback=".$L1_helpfulfeedback;
$queryString = "delete from studentanswers where L2_interestforsubject=".$L2_interestforsubject; 
$queryString = "delete from studentanswers where L2_contentclear=".$L2_contentclear; 
$queryString = "delete from studentanswers where L2_appropriateteachingpace=".$L2_appropriateteachingpace;
$queryString = "delete from studentanswers where L2_reachableforadvice=".$L2_reachableforadvice; 
$queryString = "delete from studentanswers where L2_helpfulfeedback=".$L2_helpfulfeedback; 
$queryString = "delete from studentanswers where moduleleader=".$moduleleader;
$queryString = "delete from studentanswers where lecturer1=".$lecturer1; 
$queryString = "delete from studentanswers where lecturer2=".$lecturer2; 
$queryString = "delete from studentanswers where indpstudy=".$indpstudy; 
$queryString = "delete from studentanswers where attendance=".$attendance;
$queryString = "delete from studentanswers where bestfeatures=".$bestfeatures; 
$queryString = "delete from studentanswers where improvemodule=".$improvemodule;


queryDatabase($queryString);
?>


<?php CRUDheader("Delete Student Answers"); ?>

<body>

<div id="main">

<div id="content">
<p>Student answers deleted</p>  
</div>  

</div><?php CRUDmain(); ?>

</body>
</html>

学生答案已删除

看起来你让这件事变得更难了

正如@Mave所建议的，您可以简单地

截断表studentanswers

假设您想使用delete执行此操作，那么您使用的

delete*

非常接近，但这不是正确的声明方式：

DELETE FROM STUDENTANSWERS

我会成功的

如果您有某种预配置的查询输入，其中包含一个

WHERE

，您可以执行以下操作

DELETE FROM STUDENTANSWERS WHERE 1=1

---

删除所有行。

正在运行的唯一查询是在queryDatabase（$queryString）之前分配的最后一个查询。您可以在最后一个之前删除所有$queryString=“delete…”，您的代码也会这样做

从功能上讲，这是在做同样的事情：

$queryString = "A"; //This does nothing because $queryString gets reset on the next line
$queryString = "B"; //This does nothing because $queryString gets reset on the next line
$queryString = "C"; //This does nothing because $queryString gets reset on the next line
$queryString = "delete from studentanswers where improvemodule=".$improvemodule;
queryDatabase($queryString);

回到你的问题上来。要删除所有行，只需执行以下操作：

$queryString = "delete from studentanswers where 1=1;
queryDatabase($queryString);

---

为什么不使用

截断表学生回答

？如果要选择要删除的特定行，正确的语法是

delete FROM studentanswers，其中column1=value1

delete*FROM

是无效的sql语法。delete不接受字段列表，因为您不能删除单个字段-您只能删除整行，这意味着所有字段都将被删除<代码>从表中删除是正确的syntax@Mave是否截断删除行或表？抱歉，我是新手。

TRUNCATE

清空表，保持结构完整。

DROP

命令删除整个表，包括结构。