Custom query and global variables

In WordPress, global variables are used to store data that can be accessed from anywhere within the application. Two important global variables related to querying posts are $wp_query and $post.

$wp_query is the default global variable used to store the main query result set. It is created automatically by WordPress when a request is made for a page or post. This global variable contains an instance of the WP_Query class that retrieves the posts that should be displayed on the current page. Developers can modify the $wp_query object to change the default query parameters or retrieve additional posts.

$post, on the other hand, is a global variable that contains the current post object being displayed. This variable is set by WordPress when a single post or page is being displayed. Developers can use this global variable to access the post object’s properties and metadata.

Custom queries, on the other hand, are queries that are created by developers to retrieve a specific set of posts based on custom parameters. Custom queries can be created using the WP_Query class or the get_posts() function. These queries should not modify the $wp_query global variable, but rather create a new instance of the WP_Query class or use the get_posts() function to retrieve a custom set of posts.

In summary, global variables like $wp_query and $post provide developers with a way to access data related to the current request or post being displayed, while custom queries allow for more fine-grained control over which posts are retrieved from the database.