# WordPress - Developer Resources

###### tags: `PHP` `WordPress`

> **Date**：2023/03/15
> **Taker**：Sin

This document provides a collection of useful WordPress functions for developers.

## Functions

### Retrieve a Single Row from the Database

The following function retrieves a single row from the specified database table. Replace `{{table_name}}` with the name
of your table.

global $wpdb;
$data = $wpdb->get_row('SELECT * FROM ' . $wpdb->prefix . '{{table_name}}');

[Reference](https://developer.wordpress.org/reference/classes/wpdb/get_row/)

### Retrieve an Entire SQL Result Set from the Database

This function retrieves an entire SQL result set from the specified database table. Replace `{{table_name}}` with the
name of your table.

global $wpdb;
$data = $wpdb->get_results('SELECT * FROM ' . $wpdb->prefix . '{{table_name}}');

[Reference](https://developer.wordpress.org/reference/classes/wpdb/get_results/)

### Get the Current User's ID

This function retrieves the ID of the current user. If no user is logged in, it returns 0.

$user_id = get_current_user_id();

[Reference](https://developer.wordpress.org/reference/functions/get_current_user_id/)

### Retrieve the Current User Object

This function retrieves the current user object.

$user = wp_get_current_user();

### Get Order `donate_title` and `title_type`

This function retrieves the `donate_title` and `title_type` from the `postmeta` table for all completed orders.

global $wpdb;

$data = $wpdb->get_results('SELECT order_id FROM ' . $wpdb->prefix . "wc_order_stats WHERE status = 'wc-completed' ORDER BY order_id DESC", 'ARRAY_A');

$orderIds = array_column($data, 'order_id');

$ret = $wpdb->get_results('SELECT meta_key, meta_value FROM ' . $wpdb->prefix . "postmeta WHERE post_id IN (" . implode(",", $orderIds) . ") AND (meta_key = 'donate_title' OR meta_key = 'title_type' OR meta_key = '_date_paid') ORDER BY post_id DESC", 'ARRAY_A');

var_dump($ret);

## References

1. [WordPress Developer Resources](https://developer.wordpress.org/)