Error 500 when using variables to instert to SQL database [duplicate] - php

Question

This question already has answers here:
Reference - What does this error mean in PHP?
(38 answers)
Closed 5 years ago.
I got this code, and it gives me an error 500.
I probaly got something wrong here, but i really need some help.
Here's my code
<?php include('index.php'); ?>
<?php include('config.php'); ?>
<?php
$fornavn = $_POST['fornavn'];
$efternavn = $_POST['efternavn'];
$postnummer = $_POST['postnummer'];
$alder = $_POST['alder'];
$sql = INSERT INTO medlemmer (fornavn, efternavn, postnummer, alder)
VALUES ('$fornavn', '$efternavn', '$postnummer', '$alder');
if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
$conn->close();
?>
The POST tag is the same in index.php and so.
Please help.
Thanks in advance!

Answer 1

You need to put your query in string "" first
<?php include('index.php'); ?>
<?php include('config.php'); ?>
<?php
$fornavn = $_POST['fornavn'];
$efternavn = $_POST['efternavn'];
$postnummer = $_POST['postnummer'];
$alder = $_POST['alder'];
$sql = "INSERT INTO medlemmer (fornavn, efternavn, postnummer, alder)
VALUES ('$fornavn', '$efternavn', '$postnummer', '$alder');";
if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
$conn->close();
?>
Also use prepared statement to prevent from sql injection
Turn PHP error ON so that you can get errors. Add following line in your PHP file
ini_set('display_errors',1);
error_reporting(E_ALL);

Answer 2

to first see any more possible errors, as it may help to find the problem type this at the beginning:
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);
Personally as I always used "" around the SQL-Query, and I see you haven't done it, maybe you should add them too so make it:
$sql = "INSERT INTO medlemmer (fornavn, efternavn, postnummer, alder)VALUES
('$fornavn', '$efternavn', '$postnummer', '$alder')";
Also I assume $conn is defined in your config.php?

Answer 3

As mentioned in comments first make sure you have error reporting enabled error_reporting(E_ALL); and ini_set('display_errors',1).
Also look at this SQL query string which hasn't been wrapped in quotes.
$sql = INSERT INTO medlemmer (fornavn, efternavn, postnummer, alder)
VALUES ('$fornavn', '$efternavn', '$postnummer', '$alder');
Should be
$sql = "INSERT INTO medlemmer (fornavn, efternavn, postnummer, alder)
VALUES ('$fornavn', '$efternavn', '$postnummer', '$alder')";