<?php
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);
$servername = "localhost";
$username = "root";
$password = "123456789";
$dbname = "shopdb";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT  category FROM good ";
$result = $conn->query($sql);
echo  "category: ";
while($row = $result->fetch_assoc()) {
     echo "<button>$row[category]</button>" ;
}
$conn->close();
?>