The query_posts() WordPress PHP function sets up The Loop with query parameters. This function overrides the main query and is not intended for use by plugins or themes due to its simplistic approach to modifying the main query. It’s recommended to use the ‘pre_get_posts’ action within WP_Query instead.
Usage
A generic example of how to use the function:
query_posts( array( 'category_name' => 'my-category-slug', 'posts_per_page' => -1 ) );
Parameters
$query(array|string) Required: Array or string of WP_Query arguments.
More information
See WordPress Developer Resources: query_posts()
Examples
Override the main query with all posts in a specific category
if ( is_category( 'category-slug' ) ) :
query_posts( array( 'category_name' => 'my-category-slug', 'posts_per_page' => -1 ) );
endif;
Passing variables to query_posts using concatenation
// assign the variable as current category $categoryvariable = $cat; // concatenate the query $args = 'cat=' . $categoryvariable . '&orderby=date&order=ASC'; // run the query query_posts( $args );
Passing variables to query_posts using double quotes
$current_year = date('Y');
$current_month = date('m');
query_posts( "cat=22&year=$current_year&monthnum=$current_month&order=ASC" );
Generate a complete list of posts, dealing with pagination
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
query_posts( array( 'posts_per_page' => 10, 'paged' => $paged ) );
Query posts with multiple categories and tags
query_posts( array(
'category__and' => array( 1, 3 ),
'tag__in' => array( 4, 5 ),
'posts_per_page' => 5,
'orderby' => 'date',
'order' => 'DESC'
) );