If you read this I assume you are familiar with Extract Transform and Load (ETL), this is just a short article to show how you can do ETL and especially T, the transform using a SQL statement. A word on ETL ETL is nothing new, it has been around for a while, the ETL process became a popular concept in the 1970s when computers were coming online and starting to generate digital data. Apart from storing data, the data needed a process to prepare the data for downstream applications. That is why ETL become an important concept. When data warehouses emerged in the early ’90s a centralized location for data and its transformations emerged. These data warehouses were still limited in the formats they used and the operations you could run within them, so intermediary steps (transformations) were needed before loading the data in. Since then, data warehouses and data stores in general, have added transformational abilities with SQL support, views, jobs and stored procedures. data structures Let’s first take a look at data structures and why it is important to understand that there are three common types of data structures. The why: knowing your data structure makes your task easier to select the […]