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The DISTINCT in Your COUNT

(boringsql.com)

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.

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APPROX_COUNT_DISTINCT / APPROX_DISTINCT

https://www.sketchingbigdata.org/

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Hard to make a case to engange with an AI written article even if not fully slop
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