Comment on The DISTINCT in Your COUNTComments−muth024461moIf you are satisfied with an approximation of "DISTINCT", there is a facinating probabilistic algorithm by Flajolet and Martinhttps://en.wikipedia.org/wiki/Flajolet%E2%80%93Martin_algori...which fits on 10 lines and does not require sorting. Improved versions of it are LogLog and HyperLogLog.−esafak1moAPPROX_COUNT_DISTINCT / APPROX_DISTINCThttps://www.sketchingbigdata.org/
Comments
If you are satisfied with an approximation of "DISTINCT", there is a facinating probabilistic algorithm by Flajolet and Martin
https://en.wikipedia.org/wiki/Flajolet%E2%80%93Martin_algori...
which fits on 10 lines and does not require sorting. Improved versions of it are LogLog and HyperLogLog.
APPROX_COUNT_DISTINCT / APPROX_DISTINCT
https://www.sketchingbigdata.org/