Full Mock Interview Problem Set

This capstone runs you through full mock problems that combine joins, windows, and CTEs under interview conditions. First, the meta-skill: how to behave in the room.

• Restate the problem and confirm the schema.
• Clarify edge cases (NULLs, ties, duplicates) before coding.
• Narrate your approach, then write the query.
• Test against a tiny sample in your head.

Interviewers grade your process as much as your final query.

All problems below use this small e-commerce schema. Read it once so each query makes sense.

• customers(id, name, country)
• orders(id, customer_id, order_date, status, amount)
• order_items(order_id, product_id, quantity)
• products(id, name, category, price)

Keep this in mind; the rest of the lesson references these tables.