Tatsuo Ishii makes me jealous:
Row pattern recognition (RPR) is a feature defined in the SQL standard. It allows to search for a sequence of rows by pattern. Since I am working on this feature for PostgreSQL, I would like to give a brief introduction to RPR.
This is something I’ve wanted to see in SQL Server for the past few years. It’s not something people might use every day, but it solves a particular class of problem extremely well.