APPROXIMATEDISTINCTCOUNT
Applies to: Calculated column Calculated table Measure Visual calculation
Returns an estimated count of unique values in a column. This function invokes a corresponding aggregation operation in the data source, which is optimized for query performance, but with slightly reduced accuracy. This function can be used with the following data sources: Azure SQL, Azure Synapse dedicated SQL pool, BigQuery, Databricks, and Snowflake. This function requires DirectQuery mode. Import mode and dual storage mode are not supported.
Syntax
APPROXIMATEDISTINCTCOUNT(<columnName>)
Parameters
Term | Description |
---|---|
column |
The column that contains the values to be counted. This cannot be an expression. |
Return value
The approximate number of distinct values in column
.
Remarks
The only argument to this function is a column. You can use columns containing any type of data. When the function finds no rows to count, it returns a BLANK, otherwise it returns the count of distinct values.