For windows functions a good tutorial can be found at http://tapoueh.org/blog/2013/08/20-Window-Functions

Postgresql also has good support for SQL-99 : http://www.slideshare.net/MarkusWinand/modern-sql

WITH clauses (CTE) are great, but they are "optimization fences" in Postgresql : http://blog.2ndquadrant.com/postgresql-ctes-are-optimization...