I’m looking for a way to sort products by their SKU while ignoring their prefix. The SKUs of my products have an identical prefix and a 5 digit number (eg BM12345) however some of the older products have a four digit SKU (eg BM1234). I’ve used the example code from https://gist.github.com/bekarice/1883b7e678ec89cc8f4d as a guide to do the sorting, and all the 4 digit results are listed first –

    function sv_add_sku_sorting( $args ) {

    $orderby_value = isset( $_GET['orderby'] ) ? wc_clean( $_GET['orderby'] ) : apply_filters( 'woocommerce_default_catalog_orderby', get_option( 'woocommerce_default_catalog_orderby' ) );

    if ( 'sku' == $orderby_value ) {
        $args['orderby'] = 'LENGTH(meta_value) DESC, meta_value ASC';
        $args['orderby'] = "meta_value";
        $args['order'] = 'desc'; // lists SKUs alphabetically 0-9, a-z; change to desc for reverse alphabetical
        $args['meta_key'] = '_sku';
    }

    return $args;
}
add_filter( 'woocommerce_get_catalog_ordering_args', 'sv_add_sku_sorting' );


/**
 * Add the option to the orderby dropdown.
 *
 * @param array $sortby the sortby options
 * @return array updated sortby
 */
function sv_sku_sorting_orderby( $sortby ) {

    // Change text above as desired; this shows in the sorting dropdown
    $sortby['sku'] = __( 'Sort by SKU', 'textdomain' );

    return $sortby;
}
add_filter( 'woocommerce_catalog_orderby', 'sv_sku_sorting_orderby' );
add_filter( 'woocommerce_default_catalog_orderby_options', 'sv_sku_sorting_orderby' );

Is there a way to strip the leading characters by passing another argument that will then get processed as SQL or am I on the wrong track?

eg – I tried $args['orderby'] = 'LENGTH(meta_value) DESC, meta_value DESC'; but that didn’t work.

Thank you in advance!