Error in my PHP "undefined index" and "you have an error in your SQL syntax"

Question

1.00/5 (1 vote)

See more:

WOULD JUST LIKE TO START OFF THAT I AM USING PLESK AND MYSQL AND THESE ARE THE SET PLATFORMS I HAVE TO USE FOR THIS PROJECT

I have double checked form names, everything is correct yet I am still getting the error messages. This is my PHP code:

<?php
include 'db.inc.php';
echo "The details sent down are: <br>";
echo "Title : " . $_POST['title'] . "<br>";
echo "Provider : " . $_POST['provider'] . "<br>";
echo "Description : " . $_POST['desc'] . "<br>";
echo "Fee : " . $_POST['fee'] . "<br>";
echo "Venue : " . $_POST['ven'] . "<br>";
echo "Available Places : " . $_POST['avPlaces'] . "<br>";
echo "Remaining Places : " . $_POST['rePlaces'] . "<br>";
echo "Start Date : " . $_POST['date'] . "<br>";
echo "Days : " . $_POST['days'] . "<br>";
echo "Start Time : " . $_POST['start'] . "<br>";
echo "End Time :  " . $_POST['end'] . "<br>";

$sql = "Insert into courses (Title, Provider, Description,  Fee, Venue, AvPlaces, RePlaces, StartD, Days, StartT, EndT) Values ('$_POST[title]','$_POST[provider]','$_POST[desc]','$_POST[fee]','$_POST[ven]','$_POST[avPlaces]','$_POST[rePlaces]',$_POST[date]','$_POST[days]','$_POST[start]','$_POST[end]')";
if (!mysqli_query($con, $sql))
{
	die ("An error in the sql query: " . mysqli_error($con));
}

echo "<br>A record has been added for " . $_POST['Title'] . " " ;
header("refesh:3; url=addCourse.html");

mysqli_close($con);
?>
```

and this is my HTML code accompanying it:
```

<div class="contents">
		<form action="addCourse.php" method="post">
			<label for="title" class= "label" >Title:</label><br><br>
			<input type="text" class="field" id="title" name="title"><br><br>
			<label for="provider" class= "label" >Provider:</label><br><br>
			<input type="text" class= "field" id="provider" name="provider"><br><br>
			<label for="desc" class= "label" >Description:</label><br><br>
			<input type="text" class= "field" id="desc" name="desc"><br><br>
			<label for="fee" class= "label" >Fee:</label><br><br>
			<input type="number" class= "field" id="fee" name="fee"><br><br>
			<label for="ven" class= "label" >Venue:</label><br><br>
			<input type="text" class= "field" id="ven" name="ven"><br><br>
			<label for="avPlaces" class ="label">Available Places:</label><br><br>
			<input type="number" class= "field" id="avPlaces" name="avPlaces"><br><br>
			<label for="rePlaces" class="label">Remaining Places:</label><br><br>
			<input type="number" class="field" id="rePlaces" name="rePlaces"><br><br>
			<label for="date" class="label">Start Date:</label><br><br>
			<input type="date" class= "field" id="date" name="date"><br><br>
			<label for="days" class= "label">Days:</label><br><br>
			<input type="text" class= "field" id="day" name="day"><br><br>
			<label for="start" class= "label">Start Time:</label><br><br>
			<input type="time" class= "field" id="start" name="start"><br><br>
			<label for="end" class= "label">End Time:</label><br><br>
			<input type="time" class= "field" id="end" name="end"><br><br>
			<input type="submit" id ="add" name="add"><br><br>
			<input type="reset" id = "reset" name="reset"><br><br>
			</form>
			</div>

What I have tried:

I have tried as much as I can figure for now

Posted 26-Aug-21 5:23am

Megan Crean

Updated 26-Aug-21 6:16am

Add a Solution

Comments

Richard MacCutchan 26-Aug-21 11:36am

What is the complete text of the error message? Also have you checked the ouptut of all the echo statements?

Megan Crean 26-Aug-21 11:43am

I have ran my addCourse.html page to see what would happen and this was the output:
The details sent down are:
Title : Test
Provider : Test
Description : Test
Fee : 000
Venue : Test
Available Places : 00
Remaining Places : 00
Start Date : 2021-07-20
Notice: Undefined index: days in /var/www/vhosts/C00249687.candept.com/httpdocs/Summer Project 2021/addCourse.php on line 12 Days :
Start Time : 00:00
End Time : 00:00
Notice: Undefined index: days in /var/www/vhosts/C00249687.candept.com/httpdocs/Summer Project 2021/addCourse.php on line 16 An error in the sql query: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '','','00:00','00:00')' at line 1

I checked my database to see if anything went in and no data is stored there.

Richard Deeming 26-Aug-21 11:45am

Your code is vulnerable to SQL Injection[^]. NEVER use string concatenation to build a SQL query. ALWAYS use a parameterized query.

PHP: SQL Injection - Manual[^]
PHP: Prepared statements and stored procedures - Manual[^]

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Patrice T · Answer 1 · 2021-08-26T06:16:00

PHP

$sql = "Insert into courses (Title, Provider, Description,  Fee, Venue, AvPlaces, RePlaces, StartD, Days, StartT, EndT) Values ('$_POST[title]','$_POST[provider]','$_POST[desc]','$_POST[fee]','$_POST[ven]','$_POST[avPlaces]','$_POST[rePlaces]',$_POST[date]','$_POST[days]','$_POST[start]','$_POST[end]')";

Never build an SQL query by concatenating strings. Sooner or later, you will do it with user inputs, and this opens door to a vulnerability named "SQL injection", it is dangerous for your database and error prone.
A single quote in a name and your program crash. If a user input a name like "Brian O'Conner" can crash your app, it is an SQL injection vulnerability, and the crash is the least of the problems, a malicious user input and it is promoted to SQL commands with all credentials.
SQL injection - Wikipedia[^]
SQL Injection[^]
SQL Injection Attacks by Example[^]
PHP: SQL Injection - Manual[^]
How can I explain SQL injection without technical jargon? - Information Security Stack Exchange[^]

Richard MacCutchan · Answer 2 · 2021-08-26T05:46:00

Solution 1

You have a spelling mistake: in the PHP code you are using 'days' ...

PHP

echo "Days : " . $_POST['days'] . "<br>";

... but in the HTML you are using 'day'

HTML

<label for="days" class= "label">Days:</label><br><br>
<input type="text" class= "field" id="day" name="day"><br><br>

Posted 26-Aug-21 5:46am

Richard MacCutchan

Comments

Megan Crean 26-Aug-21 11:55am

Hey, thank you for this. It resolved the Undefined Index for the days section I appreciate that. However I still have the An error in the sql query: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '','Test','00:00','00:00')' at line 1" error

Richard MacCutchan 26-Aug-21 12:05pm

Check your database schema to see what type is expected in the start time and end time fields. You should also be using a DateTime type for the start date, not a string.