percentile_tdigest()

Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer ✅ Azure Monitor ✅ Microsoft Sentinel

Calculates the percentile result from the tdigest results (which was generated by tdigest() or tdigest_merge())

Syntax

percentile_tdigest(expr, percentile1 , typeLiteral)

Learn more about syntax conventions.

Parameters

Name	Type	Required	Description
expr	string	✔️	An expression that was generated by tdigest or tdigest_merge().
percentile	real	✔️	The value that specifies the percentile.
typeLiteral	string		A type literal. If provided, the result set will be of this type. For example, typeof(long) will cast all results to type long.

Returns

The percentile value of each value in expr.

Tip

• If the type was provided, the result will be a column of the same type provided with the results of the percentile. In this case, all tdigest functions must be of that type.
• If expr includes tdigest functions of different types, don't provide the type. The result will be of type dynamic. See below examples.

Examples

The examples in this section show how to use the syntax to help you get started.

The examples in this article use publicly available tables, such as the StormEvents table in the Weather analytics sample data.

Maximum damage by state

This query aims to find the maximum property damage caused by storm events in each state.

StormEvents
| summarize tdigestRes = tdigest(DamageProperty) by State
| project percentile_tdigest(tdigestRes, 100)

Output

percentile_tdigest_tdigestRes
0
62000000
110000000
1200000
250000

Maximum damage and latest end time by state

This query aims to find the maximum property damage and the latest end time of storm events in each state.

StormEvents
| summarize tdigestRes = tdigest(DamageProperty) by State
| union (StormEvents | summarize tdigestRes = tdigest(EndTime) by State)
| project percentile_tdigest(tdigestRes, 100)

Output

percentile_tdigest_tdigestRes
[0]
[62000000]
["2007-12-20T11:30:00.0000000Z"]
["2007-12-31T23:59:00.0000000Z"]