Need help with PHP and mysql

[estcod]

Hello!

I have little problem with my code.. and my head blow up...

Code is php

<?php
include 'db.php'; if( isset($_POST['oak']) ){
$alltree = $_POST['alltree']; 
$oak= $_POST['oak'];
$sql = "UPDATE users SET $puud = $puud + 1, $sirel=$sirel+1"; 
} 
if (mysqli_query($sql)) {
 echo "'+1 Oak tree added!"; 
} ?> 
<form action="demo.php" method="post"> 
  <input type="submit" name="oak" value="Cut a tree!"> 
</form>

My vision is.. if press CUT A TREE! and page updated.. and update my oak amount at mysql data..

So, i'm newbie but i take a little journey for study :)

[Barand]

There is nothing in your form that has the name "alltree" so $_POST['alltree'] will not exist. (Turn php error reporting on. It would have told you that)

The line "$oak = $_POST['oak']" is a waste of space.

the column identifiers (puud, sire1) should not have the $s.

mysqli_query() requires 2 parameters (see manual link provided)

[estcod]

24 minutes ago, Barand said:

There is nothing in your form that has the name "alltree" so $_POST['alltree'] will not exist. (Turn php error reporting on. It would have told you that)

The line "$oak = $_POST['oak']" is a waste of space.

the column identifiers (puud, sire1) should not have the $s.

mysqli_query() requires 2 parameters (see manual link provided)

Thank you for answer..

 

<?php
           if( isset($_POST['oak']) ){
    $oak= $_POST['oak'];
    $sql = "UPDATE users SET oak=$oak+1";
            echo "You cut a tree down!";
}

           
?>
            <form action="demo.php" method="POST">
            <input type="submit" name="oak" value="Cut a tree!">
            </form>

So, now i'm thinking.. ..move right direction with this code?

Code not show errors or smth but now i stand little problem, cut a tree and page refesh show me the ECHO and not updated my oak amounts on sql.

Edited August 21, 2020 by estcod

[Strider64]

1 hour ago, estcod said:

Thank you for answer..

 

<?php
           if( isset($_POST['oak']) ){
    $oak= $_POST['oak'];
    $sql = "UPDATE users SET oak=$oak+1";
            echo "You cut a tree down!";
}

           
?>
            <form action="demo.php" method="POST">
            <input type="submit" name="oak" value="Cut a tree!">
            </form>

So, now i'm thinking.. ..move right direction with this code?

Code not show errors or smth but now i stand little problem, cut a tree and page refesh show me the ECHO and not updated my oak amounts on sql.

You're still trying to paddle upstream without a paddle. My suggestion would to be look at a CURRENT tutorial on adding, updating, and deleting  data to a database table. I would also suggest PDO instead of mysqli as I feel it's more robust, but that is a personal preference. 

I like this PDO tutorial as they do a nice job explaining how PDO works : https://phpdelusions.net/pdo

Edited August 21, 2020 by Strider64

[Barand]

if you "echo $oak" you should see that it has a value of "Cut a tree", which has a numeric value of zero.

Therefore, setting the value of your column called "oak" to $oak+1 will always result in 1.

What does this "users" table of yours look like?

[gizmola]

You don't need the value of oak to increment it within the database.

"UPDATE users SET oak = oak + 1"

With MySQL you do need to be careful with this type of update, if the original value of the oak column is NULL.  See this article on the problem.  Make sure that an uninitialized row is 0.

The obvious problem that jumps out is that this query will update ALL rows in the users table.  I think this is probably one of the things Barand noticed.  One would expect that you would be updating the row for a particular user.  If this is just for development purposes right now, then one would expect something like:

"UPDATE users SET oak = oak  + 1 WHERE id = 1"

This assumes the users table has a primary key column named id, perhaps with auto_increment, and as a user logs into the system this page would use a session variable to set the specific user row to update.