Roblox Data Scientist Data Manipulation (SQL/Python) Interview Questions
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Generate Friendship List with Acceptance Dates Using Pandas
friend_events | requester_id | accepter_id | request_date | accept_date | |--------------|-------------|--------------|-------------| | 1 |...
Analyze Recent Orders Dataset with Python/pandas
orders | order_id | user_id | price | created_at | |----------|---------|-------|------------| | 1 | 101 | 20.5 | 2024-01-01 | | 2 ...
Match requests and accepts into friendships in SQL
Given two event tables, write a single SQL query (PostgreSQL) to output unique undirected friendships with the earliest valid friendship_date. Schema ...
Clean and aggregate factory event data in Pandas
You are given three Pandas DataFrames for a factory: (1) events[event_id, machine_id, ts_utc (datetime64[ns, UTC]), event_type in {'start','stop','fau...
Implement deduped CTR/RPM aggregator over event stream
Implement a Python function to compute per-day, per-campaign CTR and RPM from an event stream with possible out-of-order and duplicate click events. I...
Compute CTR, RPM, and daily RPM variability in SQL
Write ANSI-Postgres SQL to compute, for each campaign, over the last 7 days inclusive (assume "today" is 2025-09-01, so the window is 2025-08-26 throu...
Write SQL for ads metrics and variability
Write ANSI SQL to compute daily and campaign-level metrics, including averages and standard deviations of daily CTR and CPC, using the schema and samp...
Compute ARPDAU/ARPPU by country
Using only the two tables below, write a single SQL query that returns, for each day and country in the last 7 days inclusive (2025-08-26 through 2025...
Write SQL to flag suspect payments and chargebacks
Assume today is 2025-09-01. Using only CASE WHEN and JOINs (no window functions required), write a single SQL query that produces, for each user with ...