Programmatically create post category for wordpress

wp_create_category.php

<?php

// Guessing this script is placed in the root wordpress directory.
// If not, change the require_once statements script path accordingly.
require_once('wp-load.php');
require_once('wp-admin/includes/taxonomy.php');

$conn = new mysqli('localhost', 'username', 'password', 'database');
if ($conn->connect_error) {
	die('Connection failed');
}

$result = $conn->query("SELECT category FROM table");

if ($result->num_rows > 0) {
	while($row = $result->fetch_assoc()) {
		wp_create_category($row['category'], 0); // 0 is no parent category
	}
}