dcountif() (aggregation function)
Learn how to use the dcountif() function to return an estimate of the number of distinct values of an expression for rows where the predicate evaluates to true.
Estimates the number of distinct values of expr for rows in which predicate evaluates to true.
Syntax
dcountif (expr, predicate, [, accuracy])
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| expr | string | ✔️ | The expression used for the aggregation calculation. |
| predicate | string | ✔️ | The expression used to filter rows. |
| accuracy | int | The control between speed and accuracy. If unspecified, the default value is 1. See Estimation accuracy for supported values. |
Returns
Returns an estimate of the number of distinct values of expr for rows in which predicate evaluates to true.
Example
This example shows how many types of fatal storm events happened in each state.
StormEvents
| summarize DifferentFatalEvents=dcountif(EventType,(DeathsDirect + DeathsIndirect)>0) by State
| where DifferentFatalEvents > 0
| order by DifferentFatalEvents
The results table shown includes only the first 10 rows.
| State | DifferentFatalEvents |
|---|---|
| CALIFORNIA | 12 |
| TEXAS | 12 |
| OKLAHOMA | 10 |
| ILLINOIS | 9 |
| KANSAS | 9 |
| NEW YORK | 9 |
| NEW JERSEY | 7 |
| WASHINGTON | 7 |
| MICHIGAN | 7 |
| MISSOURI | 7 |
| … | … |
Estimation accuracy
Related content
- Aggregation function types at a glance
- dcount() (aggregation function)
- countif() (aggregation function)
- count_distinctif() (aggregation function)
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