How to solve a problem using SQL?

Question

SQL

We have buyers and the products they buy.
You need to do the following:

I understand that this can be solved using PL, but I would like to understand how to do it using SQL.
That is, what request must be written in order to get what you want. (you can imagine that the tables are already there)

Answer 1

No way. The result of an SQL query is a table with the same fields in each row. It is impossible to get a different set of fields in different rows.