Couchbase N1QL's 6.5 release introduces support for window functions and common table expressions (CTE), enabling developers and data analysts to handle complex business queries more efficiently without relying on external tools like Excel. The text illustrates two examples of how these features can be used: first, by evaluating the duration of sales activities per customer in January 2019, which involves calculating total time spent and time spent by each account; and second, by analyzing month-over-month changes in sales tasks for 2018, utilizing the LAG window function to compare current and previous month task counts. These capabilities enhance the analytical power available to users, allowing for more nuanced data insights directly within the Couchbase environment.