Create data-flow-cast.md

Author: kromerm

articles/data-factory/data-flow-cast.md

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+---
+title: Rank transformation in mapping data flow 
+description: Learn how to use a mapping data flow rank transformation to generate a ranking column in Azure Data Factory or Synapse Analytics pipelines.
+titleSuffix: Azure Data Factory & Azure Synapse
+author: kromerm
+ms.author: makromer
+ms.reviewer: makromer
+ms.service: data-factory
+ms.subservice: data-flows
+ms.topic: conceptual
+ms.custom: synapse
+ms.date: 09/09/2021
+---
+
+# Rank transformation in mapping data flow 
+
+[!INCLUDE[appliesto-adf-asa-md](includes/appliesto-adf-asa-md.md)]
+
+[!INCLUDE[data-flow-preamble](includes/data-flow-preamble.md)]
+
+Use the rank transformation to generate an ordered ranking based upon sort conditions specified by the user. 
+
+> [!VIDEO https://www.microsoft.com/en-us/videoplayer/embed/RE4GGJo]
+
+## Configuration
+
+:::image type="content" source="media/data-flow/rank-configuration.png" alt-text="Rank settings":::
+
+**Case insensitive:** If a sort column is of type string, case will be factored into the ranking. 
+
+**Dense:** If enabled, the rank column will be dense ranked. Each rank count will be a consecutive number and rank values won't be skipped after a tie.
+
+**Rank column:** The name of the rank column generated. This column will be of type long.
+
+**Sort conditions:** Choose which columns you're sorting by and in which order the sort happens. The order determines sorting priority.
+
+The above configuration takes incoming basketball data and creates a rank column called 'pointsRanking'. The row with the highest value of the column *PTS* will have a *pointsRanking* value of 1.
+
+## Data flow script
+
+### Syntax
+
+```
+<incomingStream>
+    rank(
+        desc(<sortColumn1>),
+        asc(<sortColumn2>),
+        ...,
+        caseInsensitive: { true | false }
+        dense: { true | false }
+        output(<rankColumn> as long)
+    ) ~> <sortTransformationName<>
+```
+
+### Example
+
+:::image type="content" source="media/data-flow/rank-configuration.png" alt-text="Rank settings":::
+
+The data flow script for the above rank configuration is in the following code snippet.
+
+```
+PruneColumns
+    rank(
+        desc(PTS, true),
+        caseInsensitive: false,
+        output(pointsRanking as long),
+        dense: false
+    ) ~> RankByPoints
+```
+
+## Next steps
+
+Filter rows based upon the rank values using the [filter transformation](data-flow-filter.md).