Bones of SQL – Grouping By User-Defined Calendar Periods

Geschrieben von Database Magician am Dienstag, 27. September 2016

'Another tip for newcomers to SQL. Everybody knows how easy it is to group by month of the year, but what if you get a request for totals by 28 or 30 day periods starting January 1st? There is no handy DATEPART() parameter that can produce these for you. But don’t worry. There is a way that is just as easy.'...

http://www.sqlservercentral.com/articles/Date+Manipulation/145336/