Combine Category and Tag Conditions in WP_Query

A tax_query in WP_Query can hold several conditions, and its relation key decides how they are joined. The example below shows WordPress posts that are in the category new and have the tag special. A post that has only one of the two is left out.

Use the code in the template file where the list should appear, such as a page template or home.php.

<?php 
  $paged = get_query_var( "paged" )?get_query_var( "paged" ) : 1;
  $posts_per_page = -1;
  $_p = new WP_Query(array(
  	'posts_per_page'	=> $posts_per_page,
  	'paged'				=> $paged,
  	'tax_query'			=> array(
  
  		'relation' => 'AND',
  		array(
  			'taxonomy' => 'category',
  			'field'	   => 'slug',
  			'terms'	   => array('new')
  		),
  
  		array(
  			'taxonomy' => 'post_tag',
  			'field'	   => 'slug',
  			'terms'	   => array('special')
  		)
  
  	)
  ));
  
  
  while( $_p->have_posts() ):
  $_p->the_post();
  ?>


//POST TITLE
<h3><a href="<?php the_permalink(  ); ?>">
  <?php the_title(  ); ?>
  </a>
</h3>



<?php
  endwhile;
  wp_reset_query();
?>

How it works

• 'relation' => 'AND' requires every condition in the array to match. Change it to 'OR' to show posts that match either one.
• Each inner array is one condition: the taxonomy (category or post_tag), the field you match on (slug), and the terms. You can also match by term_id or name.
• terms is an array, so one condition can list several slugs; by default a post matches if it has any of them.
• posts_per_page is -1, which returns all matching posts at once, so the paged value has no effect. Set a positive number if you want pagination.

The loop prints each post’s title linked to the post. The //POST TITLE line is outside PHP and prints as text, so remove it. After a custom WP_Query loop, wp_reset_postdata() is the usual reset; wp_reset_query() is only needed after query_posts().

Related articles

• querying posts by post format: a tax_query on the built-in post_format taxonomy
• posts from a custom taxonomy term ID: the same structure for custom taxonomies
• custom field conditions with meta_query: the relation key works the same way there