Merge branch 'spagarwa-patch4' into microsoft/azure-docs/Migrations

Author: SyntaxC4

articles/data-factory/control-flow-expression-language-functions.md

@@ -60,6 +60,11 @@ Expressions can appear anywhere in a JSON string value and always result in anot
 
 ## Examples
 
+### Complex expression example
+The below example shows a complex example that references a deep sub-field of activity output. To reference a pipeline parameter that evaluates to a sub-field, use [] syntax instead of dot(.) operator (as in case of subfield1 and subfield2)
+
+@activity('{activityName}').output.{subfield1}.{subfield2}[pipeline().parameters.subfield3].{subfield4}
+
 ### A dataset with a parameter
 In the following example, the BlobDataset takes a parameter named **path**. Its value is used to set a value for the **folderPath** property by using the expression: `dataset().path`.