Query result into variable - php

Question

I'm making a website. I want it so that I can put records into the database via my website. So first I need to select the id from which record I want to change. Then I want to put the values of the selected id into a variable. The I want to put the variable into a form value.
I'm trying to make something similar to phpmyadmin. If you click on the pencil you go to a form were everything is complete and you can just change the things you want to change and save it into the database.
wijzigen.php:
<form id="form1" name="form1" method="post" action="set_wijziging.php">
<h1>Selecteer het vuurwerkid van het product dat u wilt wijzigen</h1>
<p>Vuurwerkid <br>
<input type="text" name="vuurwerkid" id="vuurwerkid" />
<input type="submit" name="wijzigen" id="wijzigen" value="wijzigen"/>
</form>
and here is the part were I put what I typed in in the form into a variable.
<?php
$vuurwerkid=$_POST["vuurwerkid"];
?>
Then I'm trying to make a query wich only selects the things were vuurwerkid='$vuurwerkid'
So here I try to put the results of the query into a variable. But this doesn't seem to work.
set_wijziging.php:
<?php
include("connect.php");
$vuurwerkid=$_POST["vuurwerkid"];
$query = "SELECT * FROM vuurwerk_info WERE vuurwerkid='$vuurwerkid'";
$resultaat = MySQL_query($query);
while ($row = MySQL_fetch_array($resultaat))
{
$vuurwerkid="$row["vuurwerkid"]";
$naam=$row["naam"];
$prijs=$row["prijs"];
$soort=$row["soort"];
$cat_vuurwerk=$row["cat_vuurwerk"];
$aantal=$row["aantal"];
}
?>
I'm just started learning PHP

Answer 1

Your where spelling is wrong in your query
Try this
$query = "SELECT * FROM vuurwerk_info WHERE vuurwerkid='$vuurwerkid'";
I miss that last time Change this line as well
$vuurwerkid="$row["vuurwerkid"]";
To this
`$vuurwerkid=$row["vuurwerkid"];
//Remove the Double queite. As its variable not string`
although function name are case-incensitive. But change theese lines as well
chnage this
$resultaat = MySQL_query($query);
while ($row = MySQL_fetch_array($resultaat))
To this
$resultaat = mysql_query($query);
while ($row = mysql_fetch_array($resultaat))
Note I change nothing in the below line. I just used the small letter to right those function
Please learn MYSQLI_ OR PDO
As mysql function are depriciated.

Answer 2

You should change your $query to
$query = "SELECT * FROM vuurwerk_info WHERE vuurwerkid='$vuurwerkid'";
Also try to echo your query to see if it's correct.
Finally as others pointed out you should stop using mysql_* and switch to msqli or PDO.