This document discusses different ways to query posts in WordPress and introduces the WP_Query class. It explains that query_posts() and get_posts() are not ideal and recommends using the WP_Query class directly. The document then lists many parameters and properties that can be used with WP_Query to customize post queries, as well as common methods like the_post() and have_posts().

1. Unlocking the Magical
Powers of WP_Query
Dustin Filippini
@dustyf
dustyf.com

2. The Loop

5. How to Get Posts?
query_posts()
Not a good way do it because it:
• Creates a new WP_Query object with
whatever parameters you set.
• Replaces the existing main query loop with a
new one (that is no longer the main query)
https://developer.wordpress.com/2012/05/14/
querying-posts-without-query_posts/

6. How to Get Posts?
get_posts()
• Returns an array of posts
• You can’t use the helper functions the_title(),
the_content, etc.
• Uncached function, so results wouldn’t be
cached in some areas like WordPress.com VIP

7. How to Get Posts?
new WP_Query()
• Sets up a new query object
• You can use the_content(), the_title(), etc.
• Actually powers both query_posts() and
get_posts() behind the scenes as well as the
main query
• Flexible to use for all kinds of post queries.

10. What is an object? A class?

11. Using the WP_Query Class

12. Some of the parameters you
can pass to WP_Query
• author
• category
• cat (id)
• category_name
• cat__in
• cat__not_in
• tax_query
• post_type
• posts_per_page
• post_parent
• post_status
• order
• orderby
• date_query
• year
• month_num
• meta_key
• meta_value
• meta_query
• has_password
• post__in
• name
• s

13. Properties of WP_Query
• $query
• $query_vars
• $queried_object
• $queried_object_id
• $posts
• $post_count
• $found_posts
• $max_num_pages
• $current_post
• $post
• $is_single, $is_page,
$is_archive,
$is_preview, $is_date,
$is_year, $is_month,
$is_time, $is_author,
$is_category, $is_tag,
$is_tax, $is_search,
$is_feed,
$is_comment_feed,
$is_trackback,
$is_home, $is_404,
and more…

14. Methods of WP_Query
• the_post()
• have_posts()
• rewind_posts()
• get_queried_object()
• get_queried_object_id()
• get( $query_var )
• set( $query_var, $value )

17. Dustin Filippini
@dustyf
dustyf.com