The proof matters
Your project is not just a set of smart queries. It is a small evidence pack.
A reviewer should be able to open your repo, load the sample data, run your SQL, compare outputs, and understand what the numbers mean.
What to submit
Use one public GitHub repository. Keep it small and easy to inspect on a phone or laptop.
Your repo should show the full path from product question to SQL answer. Do not hide the data checks or only show final screenshots.