Introduction

In the previous chapter, we discussed how to use SQL to prepare datasets for analysis. Once the data has been prepared, the next step is to analyze the data. Generally, data scientists and analytics professionals will try to understand the data by summarizing it and trying to find high-level patterns. SQL can help with this task primarily through the use of aggregate and window functions. These functions take multiple rows as input and return new information based on those input rows. To begin with, let's look at aggregate functions.