For the 'US' region, return each day's revenue and its change from the previous day's revenue (delta = today − yesterday). The very first day in the series has no previous day — treat its delta as equal to its own revenue (i.e. compare against 0, not NULL).
Expected output
day
revenue
delta
2023-01-01
550
550
2023-01-02
1010
460
2023-01-03
1020
10
First 3 of 42 rows your query should return. Your column aliases don't need to match.