UNION Joins

Abstract

In this chapter we will dive deep into the workings of the UNION join in the Data Prep Builder. To set the stage, let’s talk about what a UNION join does. A very common data scenario might involve receiving multiple text files from multiple locations within your company. Each text file contains the same columns of data, but the rows themselves will be unique. Our goal in this scenario would be to somehow combine all these individual files into one master file that contains data for every location. You might have worked through this scenario before. The brute force solution would be to open each file and copy/paste its contents into one master file. This is a reasonable solution when you are working with a small handful of files or maybe you are only doing this one time. It’s less reasonable when you have hundreds of files that you receive multiple times a week. In those cases, the UNION join will save the day!