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3-Movie Rolling Average Revenue
Calculate a 3-movie rolling average of revenue. Order movies by year then title. For each movie, show title, year, revenue_millions, and rolling_avg_revenue (average of the current movie and the 2 preceding movies, rounded to 2 decimals). Exclude movies with null revenue. This sliding window pattern is asked constantly at Meta and Google for time-series smoothing.
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Schema
movies
| id | title | year | genre | rating | votes | revenue_millions | runtime | director |
|---|---|---|---|---|---|---|---|---|
| 1 | Guardians of the Galaxy | 2014 | Action | 8.1 | 757074 | 333.13 | 121 | James Gunn |
| 2 | Prometheus | 2012 | Adventure | 7 | 485820 | 126.46 | 124 | Ridley Scott |
| 3 | Split | 2016 | Horror | 7.3 | 157606 | 138.12 | 117 | M. Night Shyamalan |
Expected output: rolling_avg: 100.00, 150.00, 150.00
Hint
Concepts
SELECT Window Functions Frame Clause ROWS BETWEEN ORDER BY
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