The main focus of this course is to help you ace the SQL interview.

It is designed to help you tackle real-world problems and make the most out of the skill level you acquire.

In the real world, theory is not enough. You’ll need exercise and practice. That’s why we designed this course around solving problems – specifically, the kind of problems that arise in interviews.

There are four levels on this learning path: Beginner, Easy, Medium, and Hard. Each of them is related to a specific set of activities you’ll need to know before becoming an expert data scientist.

At each level, you’ll learn the necessary skills to ace an interview of the same level. If you’re finding one too easy, feel free to skip to the next level.

• The beginner level is what you’ll need to know if you want to avoid using SQL. You’ll learn how to retrieve the data you need if it’s already nicely stored in a single table. If the table you get is small, you can process it elsewhere.
• The easy level will go over retrieving data, even if you have to find it by looking at different tables and finding the specific information you need.
• The medium level will teach you to retrieve the processed data you’ll need to answer most simple real-life questions on your data, but only handles one query at a time.
• The hard level will let you answer complex questions by orchestrating several queries.

At the end of the course, we’ll provide you with several tips for SQL interviews. We didn’t include them here to let you jump right into solving problems, but feel free to jump to the SQL Interview Tips section to check it out.

In general, remember to take your time with each question and make sure you’ve exhausted every possible approach before you look at the solution. We know it’s tempting to jump straight to the answer, but you’ll learn more if you actually do your best to solve each question on your own.