Extra level suggestions

[rhc2104]

Feel free to add extra level suggestions. Please remember that the lessons have to work in SQLite.

[soulomoon]

It has given some wonderful help to me learning SQL, thanks

[crazyyi]

It helps me a lot. I pick up SQL again which I haven't used for nearly a decade. Thank you very much.

[danisyellis]

A new level suggestion:
Something explaining what keys are, especially foreign keys, and how to use them to organize and get the info you need.

[jnunez2301]

On PC it would be nice to not have a scrollbar and just look at the whole page, is kinda hard to read. But yeah it helped me to get along with SQL since i didnt used it in years.