I love the work going on at w3Schools - awesome stuff!
For the SQL Tutorial, might I suggest a accessible logical model for the tables? For instance, in the "Try it" demo pages, there is a right-hand-side pane with all the available tables, but there is no way to just view the columns of those tables without leaving behind the current sql worksheet. It would be tremendously helpful if users/students could view, via some kind of client-side magic (javascript?), the model of the tables. Ideally, this would include the metadata like primary key and constraint information, but just starting with the name of the columns would be sweet.
Thanks for your time and attention.