select * from tbl TABLESAMPLE system (5)
The SYSTEM method is significantly faster than the BERNOULLI method when small sampling percentages are specified, but it may return a less-random sample of the table as a result of clustering effects.
S. Kamath, A. Orlitsky, D. Pichapati, und A. Suresh. Proceedings of The 28th Conference on Learning Theory, Volume 40 von Proceedings of Machine Learning Research, Seite 1066--1100. Paris, France, PMLR, (03--06 Jul 2015)