Order Custom Post Type Archive by multiple values in functions.php

Question

I saw this post and the function helped to fix my pagination problem for the archives pages for my custom post type: pagination doesn't show up for custom post type

The challenge I have is I need this same type of function to account for ordering the archive in ASC order and by a custom field value which is tied to a DATE value I created.

How to write the function by grabbing code from other places and trial and error?

Answer 1

Have you consulted the Codex WP_Query() entry?

To query by custom field, you'll need to add tax query parameters to your query args.

e.g.

'meta_key' => 'foobar'

To sort, you'll need to add sort and orderby query parameters to your query args.

e.g.

'order' => 'ASC',
'orderby' => 'meta_val_num'

Answer 2

^{_{pulled from OP's edit to the question}}

RESOLVED... SORT OF

I added these other $query->set parameters and it seems to work for the archive listing

/*CUSTOM ARCHIVE FOR EVENTS*/
function events_pagesize( $query ) {
    // exit out if it's the admin or it isn't the main query
    if ( is_admin() || ! $query->is_main_query() )
        return;
    // so its not admin, and its the main query, is it the tr-events post archive?
    if ( is_post_type_archive( 'tr-events' ) ) {
        // it is!! Set the posts_per_page to 6
        $query->set( 'posts_per_page', 4 );
        $query->set( 'order' , 'asc' );
        $query->set( 'meta_key', 'wpcf-tr-order-date');
        $query->set( 'orderby', 'meta_value');
        return;
    }
}
add_action( 'pre_get_posts', 'events_pagesize', 1 );

While not ideal, for other page templates, this works for the Custom Post Type Archive page.