SQL Tutorial: Joining Data in SQL | Intro

Want to learn more? Take the full course at https://learn.datacamp.com/courses/joining-data-in-postgresql at your own pace. More than a video, you'll learn hands-on coding & quickly apply skills to your daily work. --- Hi, my name is Chester Ismay and I'll be your instructor for this course on Joining Data in PostgreSQL. As the name suggests, the focus of this course is using SQL to join two or more database tables together into a single table...an essential skill for data scientists. Specifically, you'll learn how to use an INNER JOIN to match values appearing in two separate tables. You'll use OUTER JOINs to bring in all matching values as well as retain records that don't have a match. You'll use CROSS JOINs to create all combinations of fields in multiple tables. You'll investigate set operations for combining multiple tables into a single table, learn about semi-joins and anti-joins, and use nested queries (also known as subqueries) to solve tough database problems. Each chapter will close with exercises designed to help you check your understanding of the topics. By the end, you'll have the skills necessary to face any database with confidence! See you in the course! In this chapter, you'll learn about the INNER JOIN, which along with LEFT JOIN are probably the two most common JOINs. You'll see diagrams throughout this course that are designed to help you understand the mechanics of the different joins. Let's begin with a diagram showing the layout of some data and then how an INNER JOIN can be applied to that data. In the videos in this chapter and the next, we'll often work with two tables named `left` and `right`. You can see that matching values of the `id` field are colored with the same color. The `id` field is known as a KEY field since it can be used to reference one table to another. Both the `left` and `right` tables also have another field named `val`. This will be useful in helping you see specifically which records and values a