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Distinct Counts in Power BI and KQL

Dany Hoter needs a distinct count:

Calculating distinct counts on massive distributed datasets is not trivial.

Kusto (aka Azure Data Explorer/KQL database in Fabric) dcount and dcountif functions use a special algorithm to return an estimate of distinct counts

The new functions count_distinct and count_distinctif were recently added to calculate exact distinct counts. These two functions are much more expensive than the original ones.

Read on for more details on how this all works.