Database query processing?

Question

Database

Tell me, where can I see and read how requests are processed in various databases, from the receipt of a request to the issuance of data? I roughly imagine the stages: query parsing, validity check, data sampling, some additional processing (calculate the amount, for example). But I want to read specifically. Links to specific books/articles/pictures describing the architecture of these modules are welcome.
Thank you.

Answer 1

For example, here's how it's done in Oracle Database: SQL Statement Execution .
For PostgreSQL, you can start here: Overview of PostgreSQL Internals .

Answer 2

First, there are differences in these processes (mainly in relation to indexes) for different database engines. That is, there are many options.
Second, you can read about MySQL in the MySQL Reference Manual . You will have to read a lot.