Coding Codex

To get all meta keys of wp_usermeta we can easily group field of meta_key and meta_value. For example: select group_concat(meta_key) as meta_keys from wp_usermeta group by user_id limit 1 \G; Results: *************************** 1. row *************************** meta_keys: nickname,first_name,last_name,description,rich_editing,syntax_highlighting,comment_shortcuts,admin_color,use_ssl,show_admin_bar_front,locale,wp_capabilities,wp_user_level,dismissed_wp_pointers,show_welcome_panel,wp_dashboard_quick_press_last_post_id,wc_last_active,wp_user-settings,wp_user-settings-time,_previous_login,_current_login...

To easily get the last active time from users (under Woocommerce extended plugin) we can easily query from database using the meta_key of "wc_last_active" example query: select user_id, meta_value from wp_usermeta where meta_key= "wc_last_active" and user_id in (11111,112222); results: +-------------+------------------+ | user_id    | meta_value | +-------------+-------------------+ |   11111   | 1556755200 | |   112222 | 1566518400 |