How can I get the complete list of all book categories in the table?

Question

I have a "Books" table that looks like this:

I'm trying to make a Spring Boot application that lists all these books but you can filter them by category. To do this, I want to display a list of each category so the user can click on the category they want.

What is a better way to get a list of this category? For example, in the case of the picture above, I want to display a list like this:

• XXX (once only)
• YYY
• ZZZ

Answer 1

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@Query annotation @lemon provided the solution

@Query("SELECT DISTINCT category FROM Books")
List categories();

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