WP Query (Custom Query)

WP_Query adds two important functionalities within WordPress –

• You can use WP_Query to detect the type of request that WordPress is currently handling.
• You can use the various functions offered by WP_Query to perform common tasks inside loops.

tax_query:

• tax_query is a parameter available in WP_Query that helps fetch data by filtering it through taxonomies.
• It can be used to query multiple taxonomies by using the relation operator in the parameters.

meta_query:

• meta_query is a parameter available in WP_Query that helps fetch data by filtering it through the metadata of the post types.
• It can be used to query meta values by using the relation operator in the parameters.

Explore these videos for insights and tutorials on WP Query. This section comprises 3 modules with a combined duration of approximately 45 minutes.

Video Content	Time
Introduction to WP_Query	11:10
Rendering Content using WP_Query	19:29
pre_get_posts & WP_Query	14:34

For more information, you can have a look at the below resources –

• Class Reference/WP_Query
  • See especially Multiple Loops and Meta Queries.
• You Don’t Know WP_Query – Andrew Nacin
  • See Slides, especially 33 through 36 — WP_Query() by default queries & caches metadata and terms.
  • See pre_get_posts hook.
• WP_Query Arguments Guide
• Make Sense of WP_Query
• Performance Improvement (WP.com VIP)
  • Database Queries
  • Meta Queries

Coding Exercise

Go through how WP_Query works and displays the list of posts and pages with following requirements:

• Show only posts and pages with “publish” status.
• Order the list by post ID in ascending order.

Ideas to Explore:

• What is WP Query, and how does it differ from other query classes like get_posts() or query_posts()?
• How can you create a custom WP Query to fetch posts from a specific category or taxonomy?
• What are the essential parameters available for WP Query, and how do they affect the query results?
• How do meta_query and meta_key work in WP Query for querying posts with custom fields?
• How can you use WP Query to display posts in a custom order (e.g., by date, title, or custom field value)?
• How can you combine multiple taxonomies or custom field conditions in a single WP Query?
• What is the difference between pre_get_posts and WP Query for modifying query behavior?
• How can WP Query be used to fetch custom post types or hierarchical post structures?