Spin-off of "Project: Data dig" on Khan Academy. This is my final project on Advanced SQL course on Khan Academy. The task was to work with fake data and use advanced SELECT queries to discover things about the data. I chose the data about NASA astronauts and had these questions: What are average, max, and min values in the data? What about those numbers per category in the data (using HAVING)? What ways are there to group the data values that don’t exist yet (using CASE)? What interesting ways are there to filter the data (using AND/OR)?