PHP SELECT/Show last[number] items inserted in database - php

Question

In my DB I have some "documents" which contain more items, I'm inserting that from my dashboard.
The thing is ; when displaying, the method requires a value in my case it's $id.
Right now I am using rand() with hardcoded range to show different "documents".
This is how it looks :
<?php
$num = rand(1,10);
$post->showSmallPost($num);
?>
Let's say i want to have three of these on HTML page. But instead of this rand() I want to show the last three ID imported to table. So that is my question, how to do it?
This is a method showSmallPost():
public function showSmallPost($id){
$connection = new Db();
$conn = $connection->connect();
$image = new Image();
$imgC = $image->showSmallImg($id);
$query = $conn->prepare("SELECT * FROM post WHERE id = ?");
$query->bind_param('i', $id);
$query->execute();
$result = $query->get_result();
if($result->num_rows > 0) {
if ($row = $result->fetch_assoc()) {
$this->id = $row['id'];
$this->title = $row['title'];
$this->description = $row['description'];
echo "<div class=\"col-md-4 text-center\" style=\"margin-top: 5px;\">";
echo <<<EOT
<a href="news.php?post=$id">
$imgC
</a>
<h4 class="news-title">$this->title</h4>
<p class="news-para">$this->description</p>
EOT;
echo "</div>";
}
}
}
And yes, this showSmallImg() is just doing his job.

Answer 1

You can just add Sort to the Query.
You don't need to pass a random $id to the function.
You can change the SQL statement to:
$query = $conn->prepare("SELECT * FROM post ORDER BY id DESC LIMIT 0,1");
Also you can get 3 Documents in a Single Query With,
$query = $conn->prepare("SELECT * FROM post ORDER BY id DESC LIMIT 0,3");
You can even optimize the query to run faster,
$query = $conn->prepare("SELECT id, title, description FROM post ORDER BY id DESC LIMIT 0,3");
Also, rather than using HTML inside echo, you can create a multidimensional array of your preferred structure or use the one that the sql query returns.
And make use of foreach method and only print the Values inside the array with PHP and leave HTML as it is.
It will generate more cleaner code.
For Example:
<div class=col-md-4 text-center" style="margin-top: 5px;">
<?php echo $imgC; ?>
<h4 class="news-title"><?php echo $this->title; ?></h4>
<p class="news-para"><?php echo $this->description ?></p>
</div>

Answer 2

You can select the last id from the database, and create a for loop decrementing it.
$query = $conn->prepare("SELECT MAX(id) AS last_id FROM post");
$query->execute();
$result = $query->get_result();
$row = $result->fetch_assoc();
$lastId = $row['last_id'];
for ($i = $lastId; $i > $lastId - 3; $i--)
{
$post->showSmallPost($i);
}
Alternatively, you can use the ORDER BY and LIMIT statements to get what you want.
$query = $conn->prepare("SELECT id FROM post ORDER BY id DESC LIMIT 3");
$query->execute();
$result = $query->get_result();
$row = $result->fetch_assoc();
while ($row = $result->fetch_assoc())
{
$post->showSmallPost($row['id']);
}

Answer 3

If I'm understanding it right then you want to fetch the latest n records from a table and to do that you need to have a field like createdAt. Then you can write a query which will fetch the n records and order result by this createdAt field in descending order.
Your query then will look something like this
select * from posts order by createdAt desc limit 5;
This will give you the latest 5 records inserted into the table.