Update randomly indexed database columns in PHP [closed]

I am pushing a hidden field into the database that will be updated as tickets get bought; this is the field that inserts the column: <input type="hidden" class="other-bookable-tickets-sold" name="_other_tickets[-1][sold]" value="0">

What I have tried:

In the database it creates columns for each field added e.g _other_tickets[0][sold], _other_tickets[1][sold], _other_tickets[2][sold] e.t.c

How do I access and update these random columns?

// update tickets sold
function update_ticket_sold( array $tickets, $listing_id )
{
    $other_tickets = get_post_meta( $listing_id, '_other_tickets', true );
    if (isset($tickets) && is_array(($tickets))) {
        $i = 0;
        foreach ($other_tickets as $key => $ticket) {
            if (in_array(sanitize_title($ticket['name']), array_column($tickets,'ticket'))) { 
                $ids = array_keys($ticket);
                $column = '_other_tickets[' . $ids . '][sold]';
                $already_sold_tickets = (int) get_post_meta($listing_id, $column,true);
                $sold_now = $already_sold_tickets + (float) $countable[$i];
                update_post_meta($listing_id, $column, $sold_now);
                $i++;
            }
        } //end foreach
    }
}