3-Day Moving Average

For every day return the average sales over that day and up to two preceding days (fewer days at the start), rounded to two decimals.

Table schema

DailySales(sale_date DATE PRIMARY KEY, amount INT)

Sample data

sale_date | amount
2026-01-01 | 100
2026-01-02 | 200
2026-01-03 | 300
2026-01-04 | 400