Introduction to Window Functions with the same examples (salaries per department) https://www.postgresql.org/docs/13/tutorial-window.html https://www.postgresq

Introduction to Window Functions with the same examples (salaries per department) https://www.postgresql.org/docs/13/tutorial-window.html https://www.postgresql.org/docs/13/tutorial-window.html While you are at it, check out common table expressions as well https://www.postgresql.org/docs/13/queries-with.html https://www.postgresql.org/docs/13/queries-with.html