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Lesson 8 - MySQL Step By Step: More Queries And the M:N Relationship

In the previous lesson, MySQL Step By Step: Queries Over Multipe Tables (JOIN), we learned JOINs and now we can query through multiple tables. Today, we're going to continue in this manner. We'll create one more table for comments and then learn about the M:N relationship.

Comment table

We're going to extend our content management system and create a comment table. The comment (similarly as the article) is bound to the user. But it's also bound to the article. That means, we have two 1:N relationship here. One article can have N comments and also one user can have N comments. A comment always belongs to one user and one article.

Since the comment is the part and it belongs to two wholes (to the article and the user), it'll contain 2 columns with the article id and the user id. Such columns storing the id of an entry from another table are called


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Article description

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In this tutorial, we'll continue to make queries through multiple MySQL tables and learn how to create the M:N relationship using an associative table.

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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.
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