How to display category hierarchy?

Question

JavaScript

I have two tables category and subcategories, I need to get the hierarchy using Spring Boot JPA to display on the page

Hierarchy Example

• Category 1:
  
  • subcategory 2
    
  • subcategory 3
    
  
  
• Category 2
  
  • subcategory 1
    
  • subcategory 4
    
  
  

Answer 1

Maybe it doesn't reset? But it’s just that the number 10 appears there, but at the same time the style of the block is such that the unit becomes invisible?
That is, overflow and text-align:right

Answer 2

You can aggregate data in DB like this:

SELECT 
  category.id, category.title, ARRAY_AGG(subcategory.title)
FROM category
JOIN subcategory ON subcategory.category_id = category.id
GROUP BY category.id, category.title;

PostgreSQL online ARRAY_AGG