PHP : $_GET is not retrieving data from MySQL database - php

Question

I have a blog-type php site with mysql database. This blog have some lessons. There's a table "lessons", which contain id, title, text of lesson, etc.
When I display the last lessons on the main page, it works just right.
I connect to db like this:
<?php
$db = mysql_connect ("localhost", "root", "");
mysql_select_db("kursach", $db);
mysql_query("SET NAMES utf8");
$result = mysql_query ("SELECT title, meta_k, meta_d, text FROM settings
WHERE page='index' ", $db);
$myrow = mysql_fetch_array($result);
?>
and display them using loop:
<?php
$result = mysql_query("SELECT id, title, date, description FROM lessons", $db);
$myrow = mysql_fetch_array($result);
do {
printf ("<div class='right-column-content'>
<div class='right-column-content-heading'>
<a href='lesson_view.php?%s'><h1>%s</h1></a>
<h2>%s </h2>
</div>
<div class='right-column-content-content'>
<p>%s</p>
<div class='button'><a href='lesson_view.php?%s' >Читати далі</a></div>
</div>
</div>", $myrow['id'], $myrow["title"], $myrow["date"], $myrow["description"], $myrow["id"]);
}
while($myrow = mysql_fetch_array($result))
?>
I also have a file for full content of the lesson - lesson_view.php. As you can see at the code above, i send the id of lesson to link to this lesson:
lesson_view.php?%s
$myrow["id"]
In the lesson_view.php I connect to db and get the id like this:
<?php
$db = mysql_connect ("localhost", "root", "");
mysql_select_db("kursach", $db);
mysql_query("SET NAMES utf8");
if (isset($_GET['id'])) {$id = $_GET['id'];}
$result = mysql_query("SELECT * FROM lessons WHERE id = '$id' ", $db);
$myrow = mysql_fetch_array($result);
?>
And use this code to display the data:
<div class="right-column-content">
<div class="right-column-content-heading">
<h1><?php echo $myrow['title'] ?></h1>
<h2><?php echo $myrow['date'] ?> </h2>
<h2><?php echo $myrow['author'] ?> </h2>
</div>
<div class='right-column-content-content'>
<p><?php echo $myrow["text"] ?></p>
</div>
</div>
The problem is, when I try to look the full content of lesson (for exaple, /lesson_view.php?1), it doesn't display any data: no title, no text, nothing. I've tried this query directly at MySQL and it works, so, maybe there's some error in php code that I can't find. Will be thankful for any help.
P.S. I'm a beginner at php.

Answer 1

if you want to have in $_GET id then your link should be instead lesson_view.php?%s -> lesson_view.php?id=%s
for example lesson_view.php?id=5 mean that $id = $_GET['id'] will give 5, $id = 5;

Answer 2

<a href='lesson_view.php?%s'><h1>%s</h1></a>
You did not name the 'id' variable.
Change the links to
<a href='lesson_view.php?id=%s'><h1>%s</h1></a>

Answer 3

The only issue is that your printf() have 5 arguments and you are using only four and fourth one is description that you are using here
<div class='button'><a href='lesson_view.php?%s' >Читати далі</a></div>
Solution is that:
printf ("<div class='right-column-content'>
<div class='right-column-content-heading'>
<a href='lesson_view.php?%s'><h1>%s</h1></a>
<h2>%s </h2>
</div>
<div class='right-column-content-content'>
<p>%s</p>
<div class='button'><a href='lesson_view.php?id=%s' >Читати далі</a></div>
</div>
</div>", $myrow['id'], $myrow["title"], $myrow["date"], $myrow["id"], $myrow["description"]);
Move $myrow["id"] in fourth position you will get the ID as query string.
And also add the id in query string.