3. SQL for Data Preparation
In this chapter, you will learn how to clean and prepare data for analysis using SQL techniques. You will learn how to combine multiple tables and queries into a dataset using joins, unions, and subqueries. You will also use functions to transform data. These will make the data conform to certain standards before you apply advanced data analysis techniques in future chapters. By the end of this chapter, you will be able to transform and clean data using SQL functions and remove duplicate data using the
DISTINCT ON commands.