- cat (int) – use category id.
- category_name (string) – use category slug (NOT name).
- category__and (array) – use category id.
- category__in (array) – use category id.
- category__not_in (array) – use category id.
Show Posts for One Category:
Display posts that have this category (and any children of that category), using category id:
$query = new WP_Query( 'cat=4' );
Display posts that have this category (and any children of that category), using category slug:
$query = new WP_Query( 'category_name=staff' );
Display posts that have this category (not children of that category), using category id:
$query = new WP_Query( 'category__in=4' );
Show Posts From Several Categories
Display posts that have these categories, using category id:
$query = new WP_Query( 'cat=2,6,17,38' );
Display posts that have these categories, using category slug:
$query = new WP_Query( 'category_name=staff,news' );
Exclude Posts Belonging to Category
Display all posts except those from a category by prefixing its id with a ‘-‘ (minus) sign.
$query = new WP_Query( 'cat=-12,-34,-56' );
Multiple Category Handling
Display posts that are in multiple categories. This shows posts that are in both categories 2 and 6:
$query = new WP_Query( array( 'category__and' => array( 2, 6 ) ) );
To display posts from either category 2 OR 6, you could use cat as mentioned above, or by using category__in (note this does not show posts from any children of these categories):
$query = new WP_Query( array( 'category__in' => array( 2, 6 ) ) );
You can also exclude multiple categories this way:
$query = new WP_Query( array( 'category__not_in' => array( 2, 6 ) ) );
