gistfile1.txt

add_filter( 'propertyhive_search_form_fields_after', 'edit_property_search_form_fields' );
function edit_property_search_form_fields($fields)
{
    global $wpdb;
    
    $options = array('' => 'No Preference');
    
    // Query to get distinct meta values for the '_building' meta key
    $results = $wpdb->get_col(
        $wpdb->prepare(
            "
            SELECT DISTINCT pm.meta_value
            FROM {$wpdb->postmeta} pm
            INNER JOIN {$wpdb->posts} p ON pm.post_id = p.ID
            INNER JOIN {$wpdb->postmeta} pm2 ON pm.post_id = pm2.post_id
            WHERE pm.meta_key = %s
            AND p.post_type = %s
            AND p.post_status = 'publish'
            AND pm2.meta_key = %s
            AND pm2.meta_value = %s
            ",
            '_building',  // Meta key for building
            'property',   // Post type
            '_on_market', // Meta key to check
            'yes'         // Value to match
        )
    );

    // Print the distinct values
    if (!empty($results)) {
        foreach ($results as $building) {
            $options[$building] = $building;
        }
    }
    
    $fields['_building']['options'] = $options;
		
    return $fields; // return the fields
}