transactions +---------------+---------+--------+---------+---------------------+-----------------+ | transaction_id| user_id | amount | status | ts | payment_country | +---------------+---------+--------+---------+---------------------+-----------------+ | 101 | 1 | 120.50 | success | 2023-04-01 10:00:00 | US | | 102 | 2 | 980.00 | fraud | 2023-04-02 11:30:00 | CN | | 103 | 1 | 250.00 | success | 2023-04-03 09:45:00 | UK | | 104 | 3 | 1500.00| success | 2023-04-03 12:05:00 | US | +---------------+---------+--------+---------+---------------------+-----------------+ ##### Scenario You are asked to explore the transactions table and answer ad-hoc SQL questions during a live interview. ##### Question Return each user_id and the total amount of their successful transactions. 2) Add a column that classifies each transaction as 'small' (< 100), 'medium' (100- 999), or 'large' (>= 1000) using CASE WHEN. 3) List users whose total successful transaction amount exceeds 1,000; use an aggregation in the HAVING clause. ##### Hints Be explicit with CASE syntax, GROUP BY vs HAVING, and mention dialect differences if relevant.