PerlCon 2019 Rīga — Day 2 — 8 August 2019

https://perlcon.eu/talk/56

~20:00 - Window functions
~33:45 - CTE
~43:00 - Recursive CTE

This talk shows how to use SQL Window Functions (ISO SQL:2008) and how to use Common Table Expressions (CTE, ISO SQL:1999).

Using these two techniques, you can often avoid munging the query result afterwards. This potentially saves roundtrips between the program and the database.

The presentation assumes an intermediate familiarity with SQL. To get the most of the presentation, youshpuld be familiar with SELECT and JOIN. The Perl level is suitable for the beginner, but there will be very little Perl.

What are Window Functions?

Window functions are functions that perform calculations over multiple rows of the dataset while maintaining the same rows and row count of the original table.