My typical analysis workflow is to start with data in some kind of database, perhaps Redshift or Snowflake. Often I’m working with millions or even billions of rows, but modern databases excel at operating with data at scale. Moreover, SQL is an intuitive and powerful tool for combining, filtering, and aggregating data. I’ll often do as much as I can in SQL, aggregate the data as much as I can, then export the data as a CSV to continue more advanced statistical calculations in python.