PDO, $_GET, and SELECTing from MySQL Database - php

Question

So I'm working on a PHP Pastebin-esque project on my freetime to learn PHP and server management, and I've run into a LOT of issues, and I haven't been able to solve them. I decided to restart from sratch on my own with the information I've gathered so far, and threw this code together.
<?php
require 'connection.php';
$getid = $_GET["id"];
$sql = 'SELECT paste FROM pasteinfo WHERE id=:id';
$stmt = $con->prepare($sql);
$stmt->bind_param(':id', trim($_GET["id"], PDO::PARAM_INT));
$stmt->execute();
while($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
echo $row['paste'];
}
?>
What I'm trying to achieve with this code is a system where a user can type the id of whatever paste they're interested in viewing in the url and have it display the pasteinfo row, which is the row that holds the paste itself. The format they should have is viewpaste.php?id=(user input).
How can I fix this code? I would also greatly appreciate if you explain whatever code you might end up putting in the comments so I can learn from it. Thanks!

Answer 1

Try this;
connection.php
try{
$db = new PDO('mysql:host=localhost;dbname=database_name;charset=utf8mb4', 'database_username', 'database_password');
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
}
catch (PDOException $ex){
echo $ex->getMessage();return false;
}
function retrieve($query,$input) {
global $db;
$stmt = $db->prepare($query);
$stmt->execute($input);
$stmt->setFetchMode(PDO::FETCH_OBJ);
return $stmt;
}
To retrieve data, call the retrieve() function
Retrieval page, say display.php
require 'connection.php';
$getid = $_GET["id"];
$result=retrieve("SELECT paste FROM pasteinfo WHERE id=?",array($getid));
$row=$result->fetch();
//To get paste column of that id
$paste=$row->paste;
echo $paste;