I am currently using SQL in my workplace, and I have watched all the lectures from beginner to advanced to reorganize the concepts. First of all, the lecture content itself is very informative and helpful in many ways. However, the volume size of each lecture video keeps changing, and the editing in the introduction and ending of the video is not neat, so it seems a bit disappointing in terms of the quality and completeness of the lecture. Also, if the lecture materials were attached separately for the beginner/intermediate levels like this advanced lecture, it would have been more efficient to review after completing each level. The opinions on these areas for improvement are subjective, so please refer to them when creating future lectures. I sincerely thank you for creating such a good lecture, and I look forward to the new lectures that will be created in the future!