Using Common Table Expressions: Transforming and Analyzing Data in PostgreSQL, Part 2


In the first article in this transforming data series, I discussed how powerful PostgreSQL can be in ingesting and transforming data for analysis. Over the last few decades, this was traditionally done with a methodology called Extract-Transform-Load (ETL) which usually requires external tools. The goal of ETL is to do the transformation work outside of the database and only import the final form of data that is needed for further analysis and reporting.

However, as databases have improved and matured, there are more capabilities to do much of the raw data transformation inside of the database. In doing so, we