Most data engineering interview prep resources I found online were static — a list of questions with answers underneath. You read the answer, nod, and move on. A week later you can't actually write the query yourself.
So I built a small free tool that flips that: you write the actual SQL, and it checks your logic instantly instead of just showing you an answer to read.
Live here: https://harish-dataengineer.github.io/de-interview-prep/
What's in it right now:
SQL questions covering things that actually come up in interviews — finding the second highest value, detecting duplicates, running totals with window functions, gaps in a login/activity sequence
