What is the difference between materialized view and with?

Question

SQL

It seems that both the first and second statements create a temporary table. What are the differences?

I will clarify. Interesting on two DB. PostgreSQL and Oracle. Is there a difference in them?

Answer 1

materialized view - creates a very real structure where the data will be at the time of creation. If you change them in the active table, then they do not change in the view. Well, perhaps physically they are somehow tied to the data version from the current table, but that's not the point.
with is just syntactic sugar for the convenience of writing a query. Although it allows you to do things that are not possible with the usual writing of a query.