Given a table with daily amounts, write a query or script to calculate the increase in amount compared to the previous day's record and add a new column called 'Increase'.

You can use the LAG window function to compare each row with the previous day's amount:

SELECT
    Date,
    Amount,
    Amount - LAG(Amount) OVER (ORDER BY Date) AS Increase
FROM DailyAmounts
ORDER BY Date;

LAG(Amount) returns the amount from the previous row (ordered by Date). Subtracting it gives the daily increase. The first row will return NULL for Increase because there is no prior day. If you prefer a zero instead of NULL, wrap the expression with COALESCE:

COALESCE(Amount - LAG(Amount) OVER (ORDER BY Date), 0) AS Increase

This approach works in most SQL dialects that support window functions, such as PostgreSQL, SQL Server, and BigQuery.