Php retrieving number from database

Question

i'm a newbie to php still. I'm using phpmyadmin as my database. I have a table called 'lessonno' and a column named 'lesson' in it. I tried using this code to retrieve out the number inside 'lesson'. But it's not printing out anything. Can someone help?

<?php 
$server = 'localhost'; 
$username = ''; 
$password = ''; 
$database = 'project'; 
mysql_connect($server,$username,$password) or die(mysql_error());
mysql_select_db($database) or die(mysql_error());


$sql = "SELECT 'lesson' FROM 'lessonno'";
$lesson = $_POST['lesson']; 
 $result = mysql_query($sql);
?>
<?php
    for($i = 1; $i <= $lesson; $i++) {    
echo "<div>
    <a href=\"k1levelX.php?lesson=".$i."\"><span>Lesson ".$i."</span></a>           
</div>
<br>";
    }

?>

when you execute the select query inside phpmy admin,didd u get any value? — Techy
– Techy, Commented Aug 14, 2014 at 5:43
try to die(mysql_error()) like $result = mysql_query($sql) or die(mysql_error()); and see what is the error comes — Satish Sharma
– Satish Sharma, Commented Aug 14, 2014 at 5:44
you are printing $i, which is loop index!! There isn't any use of $result here, then how will you get it?? — Shaunak Shukla
– Shaunak Shukla, Commented Aug 14, 2014 at 5:45

prk · Accepted Answer · 2014-08-14 05:57:10Z

1

You can use something like this:

$sql = "SELECT lesson FROM lessonno";
$result = mysql_query($sql);
while($row = mysql_fetch_array($result)) {
echo $row['lesson'];
}

If you would like to only print out a specific lesson with an certan ID, you can use something along the lines:

$id = $_GET['lessonid']; // If you would have something like index.php?lessonid=36 and you'd like it to only fetch the data for the lesson with the id of 36. 
$sql = "SELECT lesson FROM lessonno WHERE id='$id'";

(by looking at the $_POST['lesson'] part, I suppose that's something you might be trying to do as it's in the for loop as well)

Also, I suggest you use mysqli.

And, this:

echo "<div>
    <a href=\"k1levelX.php?lesson=".$i."\"><span>Lesson ".$i."</span></a>           
</div>
<br>";

Will just echo the $i as both lesson= and the span with Lesson, which won't grab any information from the actual database but just go with the current number it's at, from the for loop you have.

edited Aug 14, 2014 at 5:57

answered Aug 14, 2014 at 5:43

prk

3,8096 gold badges20 silver badges27 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Hanky Panky Over a year ago

Also, I suggest you use mysqli.: Using mysqli with that unsafe string interpolated query will be as bad as using mysql

prk Over a year ago

@Hanky웃Panky I never said that he should use it with this specific query. I'm just saying that he should get into using mysqli instead of mysql, and if he does that he might also get into how he should do the queries. :)

Satish Sharma · Accepted Answer · 2014-08-14 07:13:31Z

1

i have made some changes in your code try this

<?php 
$server = 'localhost'; 
$username = 'root'; 
$password = ''; 
$database = 'project'; 
$conn = mysql_connect($server,$username,$password) or die(mysql_error());
mysql_select_db($database, $conn) or die(mysql_error());


$sql = "SELECT `lesson` FROM `lessonno`";
$lesson = $_POST['lesson']; 
$result = mysql_query($sql) or die(mysql_error());


while($row = mysql_fetch_assoc($result))
{
   $lesson_no = $row['lesson'];
echo "<div>
    <a href=\"k1levelX.php?lesson=".$lesson_no."\"><span>Lesson ".$lesson_no."</span></a>           
</div>
<br>";
    }

?>

Note : mysql_* is deprecated. use mysqli_* OR PDO

edited Aug 14, 2014 at 7:13

answered Aug 14, 2014 at 5:50

Satish Sharma

9,6356 gold badges31 silver badges52 bronze badges

4 Comments

Chun keat Over a year ago

@SKRocks I'm not sure why but it keep displaying this error message "Notice: Undefined index: lesson in C:\xampp\htdocs\project\k1levelselect.php on line 23"

Satish Sharma Over a year ago

@Chunkeat have you lesson column in your table lessonno

Chun keat Over a year ago

@SKRocks Yes i have the lesson column in my table lessonno

Satish Sharma Over a year ago

@Chunkeat check there is space in in column lesson before name or after? you can check this by execute query in your phpmyadmin directly

Community · Accepted Answer · 2023-11-17 19:53:52Z

0

For getting Values from DB you need to use something like this

while ($row = mysql_fetch_assoc($result)) {
 print_r($row);   
}

For further reference please visit https://www.php.net/manual/en/function.mysql-fetch-assoc.php

edited Nov 17, 2023 at 19:53

CommunityBot

11 silver badge

answered Aug 14, 2014 at 5:49

kamlesh.bar

1,81420 silver badges38 bronze badges

Comments

Ejardy · Accepted Answer · 2014-08-14 06:27:19Z

0

For counting the number of data in your database, just insert this code

$sql = "SELECT 'lesson' FROM 'lessonno'";
$lesson = $_POST['lesson']; 
$result = mysql_query($sql);
$count=mysql_num_rows($result);//this will count the number of rows in your table.

echo "<div>
<a href=\"k1levelX.php?lesson=".$count."\"><span>Lesson ".$count."</span></a>           
</div>
<br>";

answered Aug 14, 2014 at 6:27

Ejardy

1011 gold badge4 silver badges14 bronze badges

Collectives™ on Stack Overflow

Php retrieving number from database

4 Answers 4

2 Comments

4 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

4 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related