WITH
Calendar AS (
# We should be given a calendar in hand. Otherwise, assume we are oracle
# and already know the testcase.
SELECT '2018' AS year, '2018-01-01' AS start, '2018-12-31' AS end
UNION ALL
SELECT '2019' AS year, '2019-01-01' AS start, '2019-12-31' AS end
UNION ALL
SELECT '2020' AS year, '2020-01-01' AS start, '2020-12-31' AS end
)
SELECT
Product.product_id,
Product.product_name,
Calendar.year AS report_year,
(
DATEDIFF(
LEAST(Sales.period_end, Calendar.end),
GREATEST(Sales.period_start, Calendar.start)
) + 1
) * Sales.average_daily_sales AS total_amount
FROM Sales
INNER JOIN Calendar
ON (Calendar.year BETWEEN YEAR(Sales.period_start) AND year(Sales.period_end))
INNER JOIN Product
USING (product_id)
ORDER BY 1, 3;