Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
Because id cannot be null in table departments (cause PK), then no values will be provided for result.
Don't understand question :(
Yeap, you can join same table multiply times if it's needed
You need to check, that there is not eval func in solution.