Real use of this query: Hospitals in the UK are penalised if patients have to wait too long for their operations. If the patient cancels an appointment the timer is reset on the waiting time. if the hospital cancels, the waiting time is not reset. (It's actually a lot more complex, but that's the basic principle)

Last year I was asked to sort out some ETL stored procedures used in waiting time calculations that were taking over 20 hours to run. These procs were using cursors. I replaced the stored procs with ones using very similar code to that shown here. The run time dropped from 20 hours + to less than 10 minutes.

Hope that's real enough 🙂

Glyn