Summary
In this chapter, we explored how to use window functions. We have seen that by using window functions, we can create more complex aggregates compared to those made with the GROUP BY statement, which we saw in Chapter 5, Advanced Statements. We learned how to use the ROW_NUMBER (), FIRST_VALUE (), LAST_VALUE (), RANK DENSE_RANK(), LAG (), LEAD (), CUME_DIST (), and NTILE () functions. We have also seen the difference between creating aggregates with the ROWS BETWEEN and RANGE BETWEEN clauses. You can use what you have learned in this chapter in data mining operations to make your work much easier.
For more information on window functions, you can consult the official documentation: https://www.postgresql.org/docs/current/functions-window.html.
In the next chapter, we will talk about server-side programming. We will look at how to create functions to be used on the server side and, if necessary, where to use window functions.