I really enjoyed learning about many queries and functions, and the knowledge that you can derive results in various ways. As I listened to the lecture, I realized that the more I know about the functions provided by the DBMS, the cleaner the query results I can derive. I also realized that the way I used to write queries in practice was to simply solve problems with subqueries. If I can freely apply the techniques you taught me to practice, I think I will be able to write SQL more enjoyably. Thank you for your hard work and sharing your great knowledge in this lecture!