Get up to 80 % extra points for free! More info:

Lesson 10 - MySQL Step By Step: Subqueries

In the previous lesson, MySQL Step By Step: Exercises to practise, we practiced queries on several examples. Today's lesson is all about subqueries, so it's going to complete our knowledge of the SQL basics.


A subquery is a query that's part of another query. Right, we can nest queries into another. Like this, we can use the output of one query as an input for another query because it's basically also a data table. In practice, this is widely used, and we have the ability to get all the results straight from the database that we'd otherwise have to put together in our application.

Of course, subqueries are performance-intensive, but if they're optimized properly (see the next lessons) they should be faster than using multiple separate queries or JOINs.

Try to think about how'd you list articles of the user whose nickname is "David". You might think of the following query:


...End of the preview...
Continue further

You will gain knowledge worth hundreds of thousands for a few crowns

You've come here and that's great! We believe that the first lessons showed you something new and useful
Do you want to continue the course? Go to the premium section.

Limited offer: Learn all knowledge and save money

Buy all currently available lessons with exercise submitting and other features for an exclusive price $3.87
Current account balance $0
By buying this exclusive package, you'll have access to all 13 lessons in this course including exercise submitting while saving $0.63. This offer is limited for the first lessons only with an additional exclusive 15% discount.

Before buying this article, you have to buy the previous one

This article is licensed: Premium, by buying this article, you agree with the terms of use.

What will you get from us in the next lessons?
  • Unlimited and permanent access to individual lessons.
  • High quality IT knowledge.
  • Skills to help you get your dream and well-paid job.

Article description

Requested article covers this content:

In this tutorial, we'll learn to use subqueries, nested queries in MySQL database. We'll explain new operators: IN, ALL, ANY, and EXISTS.

You gain credits by supporting our network. This is done by sending a helpful amount of money to support the site, or by creating content for the network.

Article has been written for you by David Capka
The author is a programmer, who likes web technologies and being the lead/chief article writer at He shares his knowledge with the community and is always looking to improve. He believes that anyone can do what they set their mind to.
Unicorn university David learned IT at the Unicorn University - a prestigious college providing education on IT and economics.