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data-explorer/kusto/query/rowrankfunction.md

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+---
+title: row_rank() - Azure Data Explorer | Microsoft Docs
+description: This article describes row_rank() in Azure Data Explorer.
+services: data-explorer
+author: royo
+ms.author: royo
+ms.reviewer: alexans
+ms.service: data-explorer
+ms.topic: reference
+ms.date: 01/28/2021
+---
+# row_rank()
+
+Returns the current row's rank in a [serialized row set](./windowsfunctions.md#serialized-row-set).
+The row index starts by default at `1` for the first row, and is incremented by `1` whenever the provided *Term* is different than the previous row's *Term*.
+
+## Syntax
+
+`row_rank` `(` *Term* `)`
+
+* *Term* is is an expression indicating the value to consider for the rank. The rank is increased whenever the *Term* changes.
+
+## Returns
+
+The function returns the row rank of the current row as a value of type `long`.
+
+## Example
+
+This example shows how one can rank the `Airline` by the number of departure from the *SEA* `Airport`:
+
+```kusto
+datatable (Airport:string, Airline:string, Departures:long)
+[
+  "SEA", "LH", 3,
+  "SEA", "LY", 100,
+  "SEA", "UA", 3,
+  "SEA", "BA", 2,
+  "SEA", "EL", 3
+]
+| sort by Departures asc
+| extend Rank=row_rank(Departures)
+```
+
+Running this query produces the following result:
+
+Airport  | Airline  | Departures  | Rank
+---------|----------|-------------|------
+SEA      | BA       | 2           | 1
+SEA      | LH       | 3           | 2
+SEA      | UA       | 3           | 2
+SEA      | EL       | 3           | 2
+SEA      | LY       | 100         | 3