Data Engineer
SQL questions
24 questions on SQL for data engineers, easiest first.
Easy 6
Medium 10
- Upserting into a target tablemedium
- Keeping the latest row per keymedium
- RANK and DENSE_RANK with tiesmedium
- NOT IN with a NULL in the listmedium
- Day-over-day change with LAGmedium
- WHERE filter after a LEFT JOINmedium
- Counting orders for every customermedium
- Table state after a MERGEmedium
- Revenue doubled after a joinmedium
- Employees above their team averagemedium