First Order per Customer
Solve this the way you would in the interview: out loud, on a timer, with an AI interviewer asking follow-ups while you code. You get a scored report at the end.
Practice this as a mock interviewFree to start, no account neededProblem
Table orders:
id INTEGER primary key
customer_id INTEGER never NULL
placed_at TEXT 'YYYY-MM-DD HH:MM'
total REAL
Return each customer's first order. If a customer placed two orders in the same minute, the one with the lower id is first.
Columns, in this order: customer_id, order id, placed_at, total.
Order by customer_id, ascending.
Examples
Constraints
- Exactly one row per customer, even when timestamps tie.
What the interviewer grades
A correct solution is one of five scores. The report also grades problem understanding (did you clarify inputs and edge cases before coding), problem solving, communication while you work, code quality, and testing. See a sample report, or read up on the pattern in the lessons.