Part 98: Cumulative Running Totals & Moving Averages

Running balances are ubiquitous in banking, inventory, and SaaS subscription tracking.

1. Running Total Syntax

SELECT 
  transaction_date,
  amount,
  SUM(amount) OVER (
    ORDER BY transaction_date, id
    ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
  ) AS account_balance
FROM bank_transactions;

Key Takeaways

• SUM() OVER (ORDER BY ...) calculates cumulative balances on the fly.

In Part 99, we explore Named Windows with the WINDOW Clause!