Set username as author of comment in php/mysql - php

Question

So I'm making a website where registered users are able to make a post, comment on the post as well as reply to the comments and I'm having trouble with displaying the username of whom has commented.
File home.php
<?php
$sql = "SELECT * FROM post LIMIT 3";
$result = $conn->query($sql);
while ($row = mysqli_fetch_assoc($result)){
$id = $row['users_id'];
$sql2 = "SELECT * FROM users WHERE users_username='$id'";
$result2 = $conn->query($sql2);
if($row2 = mysqli_fetch_assoc($result2)){
echo "<div class='comment-box'>";
echo $row['title']."<br>";
echo $row['date_created']."<br>";
echo $row2['users_id']."<br>";
echo $row['content']."<br>";
echo "</p></div>";
if(isset ($_SESSION["username"])){
echo "<button type='button' id='postbtn' onclick='replyFunction()'>Reply</button>";
include 'commentsection.php';
}
}
}
File makeapost.php
<div class="thread">
<form action="<?php echo htmlspecialchars("includes/posts.inc.php");?>"method="post">
<h4>Create a post </h4>
<hr></hr>
<input type="hidden" name="post_id">
<input type="hidden" name="users_id" value="<?php echo ".$_SESSION[username].";?>">
<input type="text" id="thetitle" name="title" placeholder="Title">
<input type="hidden" name="date_created"> <br>
<textarea id="summernote" name="content"></textarea>
<hr></hr>
<button type="submit" id="postbutton" name="submit">Post</button>
</form>
</div>
File posts.inc.php
<?php
include 'dbh.inc.php';
include 'functions.inc.php';
if (isset($_POST["submit"])){
$title = $_POST["title"];
$users_id = $_POST["users_id"];
$content = $_POST["content"];
$date_created = $_POST["date_created"];
$mysqltime = date ('Y-m-d H:i:s');
$sql = "INSERT INTO post (title, users_id, content, date_created) VALUES (?,?,?,?);";
$stmt = mysqli_stmt_init($conn);
if (!mysqli_stmt_prepare($stmt, $sql)){
header("location: ../home.php?error=stmtfailed");
exit();
}
mysqli_stmt_bind_param($stmt, "ssss", $title, $users_id, $content, $mysqltime);
mysqli_stmt_execute($stmt);
mysqli_stmt_close($stmt);
header("location: ../home.php?error=none");
exit();
}
login.inc.php
<?php
if (isset($_POST ["submit"])){
$username = $_POST["username"];
$password = $_POST["password"];
require_once 'dbh.inc.php';
require_once 'functions.inc.php';
if(emptyInputLogin($username, $password) !== false){
header("location: ../home.php?error=emptyinput");
exit();
}
loginUser($conn, $username, $password);
} else {
header("location: ../home.php");
exit();
}
functions.inc.php
function loginUser($conn, $username, $password){
$uidExists = uidExists($conn, $username, $username);
if($uidExists === false){
header("location: ../login.php?error=wrongusername");
exit();
}
$passwordHashed = $uidExists["users_password"];
$checkPwd = password_verify($password, $passwordHashed);
if($checkPwd === false){
header("location: ../login.php?error=wrongpassword");
exit();
} else if ($checkPwd === true){
session_start();
$_SESSION["userid"] = $uidExists["users_id"];
$_SESSION["username"] = $uidExists["users_username"];
$_SESSION["role"] = $uidExists["users_role"];
header("location: ../home.php");
exit();
}
}
Table structure
CREATE TABLE IF NOT EXISTS `post` (
`post_id` int(11) NOT NULL AUTO_INCREMENT,
`users_id` int(11) NOT NULL,
`content` varchar(500) NOT NULL,
`date_created` varchar(500) NOT NULL,
PRIMARY KEY (`post_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=14;
CREATE TABLE IF NOT EXISTS `users` (
`users_id` int(11) NOT NULL AUTO_INCREMENT,
`users_username` tinytext NOT NULL,
`users_password` longtext NOT NULL,
PRIMARY KEY (`users_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=6 ;
It may have something to do with the fact that I cannot connect the right user ID from the post table to the users table, since in the users table i have columns such as (users_id(AUTO_INCREMENT), users_username)
but in post table i have (users_id). I am able to make a post and messages are inserted to the database, but theres no users shown.
Any tips on how I can improve this? Right now nothing is being displayed on home.php page, but the posts are still in the database.

Answer 1

Working from the table definitions you posted above (which don't match your PHP code) I created this data:
post table:
post_id
users_id
content
dateCreated
14
6
Here's some content
20 May 2022
15
7
A message
19 May 2022
16
7
Another message
20 May 2022
17
8
I've nothing to say
20 May 2022
18
9
I said everything already.
18 May 2022
Users table
users_id
users_username
users_password
6
Mike
password
7
George
another password
8
Helen
passwd
9
Alice
pword
10
Bob
secret
From this I created this query:
select post_id, content, date_created, u.users_username
from
post
join
(select users_username, users_id from users) u
on post.users_id = u.users_id
order by date_created desc
limit 3;
Which gives this result:
post_id
content
date_created
users_username
14
Here's some content
20 May 2022
Mike
16
Another message
20 May 2022
George
17
I've nothing to say
20 May 2022
Helen
Now you can just loop through the results and create your output without the need for a nested query to retrieve data.
Note:
This is a simple example based on your table structure and some simple data. You can include or exclude some of these columns, change the order, include or exclude more rows.
dateCreated should be a DateTime column, not a varchar column
Passwords should NOT be stored in plain text.
You will need to consider appropriate indexing once these tables start to grow.