sample-distinct operator

Returns a single column that contains up to the specified number of distinct values of the requested column.

The operator tries to return an answer as quickly as possible rather than trying to make a fair sample.

Syntax

T | sample-distinct NumberOfValues of ColumnName

Learn more about syntax conventions.

Parameters

Name	Type	Required	Description
T	string	✔️	The input tabular expression.
NumberOfValues	int, long, or real	✔️	The number distinct values of T to return. You can specify any numeric expression.
ColumnName	string	✔️	The name of the column from which to sample.

Tip

• Use the top-hitters operator to get the top values.
• Refer to the sample operator to sample data rows.

Examples

Get 10 distinct values from a population

Run the query

StormEvents | sample-distinct 10 of EpisodeId

Sample a population and do further computation without exceeding the query limits in the summarize

Run the query

let sampleEpisodes = StormEvents | sample-distinct 10 of EpisodeId;
StormEvents 
| where EpisodeId in (sampleEpisodes) 
| summarize totalInjuries=sum(InjuriesDirect) by EpisodeId