In our recent article on setup_postdata(), a reader posted a good question: how to sort a fetched array of WP_Post objects alphabetically by their terms in a given taxonomy?

Recently, I was working on site speed for a client with one page that makes a large number of custom database queries through WordPress’s WP_Query API.

Something I can’t remember needing to do before is to paginate a custom WP_Query. (Maybe my memory’s failing me, since this is what you’d need to know how to do to put post content at the top of an archive page—one of the weirdest and most common “Why can’t WordPress do that?” things in my experience.)

Recently, a client project I’m working on required something I don’t think I’ve done before: write a WP_Query to fetch a dynamically generated list of post IDs.

Making a widget to show a random post uses two underlying concepts you need to get familiar with to be good at WordPress development: making use of WP_Query objects, and making widgets. If you’ve not checked them before, check out our Quick Guides which more thoroughly introduce both:

We’re doing a WordPress development training session tomorrow!

Using WP_Query for the first time can be scary. If you’re an established programmer who is well acquainted with object-oriented programming, it’s pretty easy. But if you’re not you need to use WordPress’s looping concept, and an object, for the first time, and it’s a lot to take in. Don’t get overwhelmed. Copying and pasting the first few (dozen) times is how everyone learns. My hope is that the video gives you some understanding though:

This is not a new resource, but I just rediscovered and found it still incredibly relevant. Back in 2011, Andrey “Rarst” Savchenko put together a little diagram that shows the difference between three of the most common ways of dealing with getting posts in WordPress, a new WP_Query object, or the query_posts() or get_posts() functions.

I really enjoyed David’s article from a few weeks ago on the basics of functional programming as it applies to WordPress’s nested data structures. One of the nice things about working with him is that I learn a lot, too. Today, I want to continue exploring the somewhat-functional world David introduced, and suggest some freer ways of interacting with a very important entity in WordPress: the WP_Query object.

WP_Query is an exceptionally powerful tool in WordPress. Every WordPress site contains a database that stores many posts (of many post types) that make up the bulk of that site’s content, and WP_Query is the best way to fetch or retrieve a given selection of those posts for processing.