What is: WP_Query

Keeping in mind that all of the software powering WordPress is written in the PHP programming language, wp_query is a way for developers to perform certain things such as creating custom queries that deal with class references for posts and pages.

As this is a powerful tool, using wp_query is recommended for professional developers only.

The command wp_query, just as you might expect, performs a query of the WordPress database. For example, here’s a very basic wp_query that will return only posts that fall into the movies category:

<?php
// The Query
$the_query = new WP_Query( 'category_name=movies' );
 
?>

Keep in mind that the above code will not (automatically) display the relevant posts. In order to do that, you need to write a more complicated wp_query like this:

<?php
// The Query
$the_query = new WP_Query( 'category_name=movies' );
 
// The Loop
if ( $the_query->have_posts() ) {
        echo '<ul>';
    while ( $the_query->have_posts() ) {
        $the_query->the_post();
        echo '<li>' . get_the_title() . '</li>';
    }
        echo '</ul>';
} else {
    // no posts found
}
/* Restore original Post Data */
wp_reset_postdata();
 
?>

The wp_query is a very versatile and powerful code and can be used to write very complex queries. You can also use wp_query to create nested loops. The wp_query query is very useful for creating plugins and themes in order to create custom ways for posts (and pages) to be displayed.