I want to filter search results by custom post type and custom taxonomy terms, the result is here:

add_action('pre_get_posts','search_filter');
function search_filter($query) {
    if($query->query_vars['s'] != '' && is_search())
    {
        $query->set('post_type', array('partner','event','product'));
        $tax_query = array(
            'relation' => 'OR',
            array(
                'taxonomy' => 'city',
                'field'    => 'slug',
                'terms'    => array( 'belgrade' )
            )
        );
        $query->set( 'tax_query', $tax_query );
    }
}

Posts from specific CPT works, but filter by a category, not. Why? :)

I want to filter search results by custom post type and custom taxonomy terms, the result is here:

add_action('pre_get_posts','search_filter');
function search_filter($query) {
    if($query->query_vars['s'] != '' && is_search())
    {
        $query->set('post_type', array('partner','event','product'));
        $tax_query = array(
            'relation' => 'OR',
            array(
                'taxonomy' => 'city',
                'field'    => 'slug',
                'terms'    => array( 'belgrade' )
            )
        );
        $query->set( 'tax_query', $tax_query );
    }
}

Posts from specific CPT works, but filter by a category, not. Why? :)

• wp-query
• filters
• search

• is_search always refers to $wp_query->is_search(), but what if $query is not the main query? Then the if statement won't match because $query->is_search() might be true, but is_search() will be false! Otherwise the result of this appears to be that you want to search 3 post types, but only the posts that are in the city of belgrade – Tom J Nowell ♦ Commented Feb 22, 2022 at 10:48
• I want to be safe to filter query only on the search page. – Milosh N. Commented Feb 22, 2022 at 10:51

1 Answer 1

I think the issue here is you're using the relation where you only have one inner tax array. So, it should be without one.

$tax_query = array(
      array(
         'taxonomy' => 'city',
         'field'    => 'slug',
         'terms'    => array( 'belgrade' )
   )
);

Here's a detailed explanation from WP: Taxonomy Parameters

• relation (string) – The logical relationship between each inner taxonomy array when there is more than one. Possible values are ‘AND’, ‘OR’. Do not use with a single inner taxonomy array.