How to Calculate a Cumulative Percentage in SQL

A fun report to write is to calculate a cumulative percentage. For example, when querying the Sakila database, we might want to calculate the percentage of our total revenue at any given date. The result might look like this: Notice the beautifully generated data. Or as raw data: payment_date |amount |percentage -------------|--------|---------- 2005-05-24 |29.92 |0.04 … Continue reading How to Calculate a Cumulative Percentage in SQL

Lesser Known jOOλ Features: Useful Collectors

jOOλ is our second most popular library. It implements a set of useful extensions to the JDK's Stream API, which are useful especially when streams are sequential only, which according to our assumptions is how most people use streams in Java. Such extensions include: // (1, 2, 3, 1, 2, 3, 1, 2, 3, 1, … Continue reading Lesser Known jOOλ Features: Useful Collectors