Tags, use both union and intersection at the same time

Question

I have tags on posts and I want a display based on the following logic: If it has the "biology" tag AND it has either the "female" or "male" tag.

biology AND (female OR male)

Here's what I attempted but it didn't work: http://www.example.org/tag/biology+female,male

Obviously the above is ambiguous, is there a way to do what I'm needing?

Answer 1

You can achieve this with a tax_query, though by default not via any sort of URL manipulation:

$args = array(
    'post_type' => 'post',
    'tax_query' => array(
        'relation' => 'AND',
        array(
            'taxonomy' => 'post_tag',
            'field' => 'slug',
            'terms' => array( 'biology' )
        ),
        array(
            'taxonomy' => 'post_tag',
            'field' => 'slug',
            'terms' => array( 'male', 'female' ),
            'operator' => 'IN'
        )
    )
);
$query = new WP_Query( $args );

If you wanted to do this via URL, you'd have to come up with some way to pass the terms so you could intercept and create the query.