Course

SQL Subqueries

In this course, you’ll learn how to nest queries inside other queries.

Enroll for free

Part of the SQL, and Power BI paths.

4.8 (359 reviews)

6,491 learners enrolled in this course.

Intermediate friendly
6 hours
Self paced
6 lessons

“Getting a data science job would have been much harder without Dataquest. It’s a great product. I recommend it to anyone who asks me about how to get started.”

Adam Zabrodski

Data Science Manager @ Later

SQL Subqueries

Enroll For Free

Course overview

A subquery is a query nested inside another query. Subqueries are useful to data practitioners for scaling and making more powerful queries. The main reason we have subqueries is the need to combine information from multiple tables. Information in a relational database isn’t stored in a single table; it’s shared between several tables.

In this course, you’ll learn various types of subqueries, how to use them, and why they are so valuable: scalar subquery, multi-rows subquery and multi-columns subquery. You’ll also learn how to write common table expressions in SQL.

Best of all, you’ll learn by doing — you’ll practice and get feedback directly in the browser.

Key skills

Nesting a query inside another query
Employing different types of subqueries
Employing common table expressions
Scaling your project with complex queries

Course outline

SQL Subqueries [6 lessons]

Scalar Subqueries in SQL 1h

Lesson Objectives

Extract a single value from a subquery
Employ a single value subquery in your queries
Identify why subqueries are useful

Multi-row and Multi-column Subqueries in SQL 1h

Lesson Objectives

Extract multiple rows from a subquery
Extract multiple columns from a subquery
Scale your project with multi-row subqueries

Nested and Correlated Subqueries in SQL 1h

Lesson Objectives

Nest a subquery inside another subquery
Write dependent subqueries
Write effective queries

Common Table Expression in SQL 1h

Lesson Objectives

Write Common Table Expressions (CTEs)
Write Recursive Common Table Expression

Views in SQL 1h

Lesson Objectives

Explain the concept and application of views in SQL
Create views
Query views
Create views from views
Drop views

Guided Project: Customers and Products Analysis Using SQL 1h

Lesson Objectives

Expand your portfolio using real-world data

The Dataquest guarantee

Dataquest has helped thousands of people start new careers in data. If you put in the work and follow our path, you’ll master data skills and grow your career.

We believe so strongly in our paths that we offer a full satisfaction guarantee. If you complete a career path on Dataquest and aren’t satisfied with your outcome, we’ll give you a refund.

Master skills faster with Dataquest

Go from zero to job-ready

Learn exactly what you need to achieve your goal. Don’t waste time on unrelated lessons.

Build your project portfolio

Build confidence with our in-depth projects, and show off your data skills.

Challenge yourself with exercises

Work with real data from day one with interactive lessons and hands-on exercises.

Showcase your path certification

Impress employers by completing a capstone project and certifying it with an expert review.

Grow your career with
Dataquest.

98%

of learners recommend

Dataquest for career advancement

4.9

Dataquest rating on

G2Crowd and SwitchUp

$30k

Average salary boost

for learners who complete a path

Aaron Melton

Business Analyst at Aditi Consulting

“Dataquest starts at the most basic level, so a beginner can understand the concepts. I tried learning to code before, using Codecademy and Coursera. I struggled because I had no background in coding, and I was spending a lot of time Googling. Dataquest helped me actually learn.”

Jessica Ko

Machine Learning Engineer at Twitter

“I liked the interactive environment on Dataquest. The material was clear and well organized. I spent more time practicing then watching videos and it made me want to keep learning.”

Victoria E. Guzik

Associate Data Scientist at Callisto Media

“I really love learning on Dataquest. I looked into a couple of other options and I found that they were much too handhold-y and fill in the blank relative to Dataquest’s method. The projects on Dataquest were key to getting my job. I doubled my income!”