I can't help but write a review. Thank you for creating such a great lecture. On the one hand, I was embarrassed that I didn't know much about queries, but you explained them in detail through rich PPTs and then immediately practiced each example one by one. During the practice, the teacher gave me some practical knowledge, which was also very helpful. Also, you gave me detailed answers to my questions, which helped me a lot in my studies, and you also gave me very detailed answers to the questions that other people left, so I was able to study a lot and gain insight just by reading them. Specifically, I was really surprised and grateful that I could understand join, left join, right join, full outer join, group by, and having in just a few lectures. And when I Googled the content related to rank in Analytic Query, I didn't know exactly what I was using, but This lecture helped me build a solid foundation. I first heard about Analytic Query, so I was a bit reluctant at first, but I found out that I had used it before, so I was happy and was able to listen to the lecture with enjoyment. To summarize, 1. I really liked the rich PPT lecture and the fact that I could practice Query with real-world data. 2. The answers to the questions were so detailed that I could gain new insights or study a lot just by reading the answers. Even though I read a question from 2-3 years ago and asked a question, the instructor answered me in detail without losing the context of the question and answer from several years ago. 3. If you search Google, there are many examples of set diagrams related to join, but this one is much more clear. 4. I think this is a really great lecture for building the basics of Analytic Query. 5. Users who use Mac or DataGrip may have a hard time at first because they cannot import the .backup file. However, I tend to solve various errors I encounter in class myself and ask only about things that I really can't solve, and I was able to learn a lot while solving that issue. You made a lecture that explained this part additionally, so I was able to practice queries with the data you prepared while using Mac and DataGrip without any problems. Thank you so much. I will purchase other lectures and study them. Thank you so much for sharing your knowledge.