Basic SQL Exercise + Learning/Skill-Growth Discussion

Part A: SQL (basic) Given a table events with: user_id (string) event_time (timestamp) event_type (string) value (numeric) Write SQL for (implement 1–2 as requested): Daily active users (DAU) by day. P95 of value per event_type (if P95 isn’t supported, explain an alternative). Each user’s first event time and the corresponding event type. Part B: Learning / skill growth Describe a time you had to ramp up on a critical skill quickly (SQL/cloud/data engineering/optimization). How did you plan, validate proficiency, and turn it into impact? Constraints State your timezone/day-bucketing assumptions. Explain how you handle duplicates or late events. Example Input events user_id,event_time,event_type,value u1,2025-01-01 01:00:00,click,1 u1,2025-01-01 02:00:00,view,3 u2,2025-01-01 03:00:00,click,2 u2,2025-01-02 01:00:00,view,5 Output DAU: 2025-01-01 -> 2 2025-01-02 -> 1 (first event per user: u1=2025-01-01 01:00:00 click; u2=2025-01-01 03:00:00 click)