dcount() (aggregation function)
Learn how to use the dcount() function to return an estimate of the number of distinct values of an expression within a group.
Calculates an estimate of the number of distinct values that are taken by a scalar expression in the summary group.
Syntax
dcount (expr[, accuracy])
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| expr | string | ✔️ | The input whose distinct values are to be counted. |
| accuracy | int | The value that defines the requested estimation accuracy. The default value is 1. See Estimation accuracy for supported values. |
Returns
Returns an estimate of the number of distinct values of expr in the group.
Example
This example shows how many types of storm events happened in each state.
StormEvents
| summarize DifferentEvents=dcount(EventType) by State
| order by DifferentEvents
The results table shown includes only the first 10 rows.
| State | DifferentEvents |
|---|---|
| TEXAS | 27 |
| CALIFORNIA | 26 |
| PENNSYLVANIA | 25 |
| GEORGIA | 24 |
| ILLINOIS | 23 |
| MARYLAND | 23 |
| NORTH CAROLINA | 23 |
| MICHIGAN | 22 |
| FLORIDA | 22 |
| OREGON | 21 |
| KANSAS | 21 |
| … | … |
Estimation accuracy
Related content
- Aggregation function types at a glance
- dcountif() (aggregation function)
- count()
- count_distinct() (aggregation function)
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