Wordpress generates ID's for each page/post. Do pages in wordpress share the same ID column in the database as the posts? I mean, if a site has both posts and pages, can one or more page_ID's be same as some Post_ID's?
No, all posts, pages and other custom post types exist in the same table (
wp_posts) and they all share the same ID column. The ID is unique to each entry regardless of its post type.