How does the database make it possible to separate a product by color and size in stock?

Question

Database design

Tell me how they make a database for stores.
We have a table of products.
How can we make a choice of color and size for each product?
It under each product one more table needs to be created?

Answer 1

EAV or jsonb type field for characteristics.

Answer 2

It under each product one more table needs to be created?

No, the key is not a product, the key is a SKU.
https://ru.wikipedia.org/wiki/SKU

Answer 3

The easiest way is to store each type of product as a separate product. prices depending on the size may also differ, and the availability in the warehouse is also different for each modification. Just when displaying the range, group the variations into one.