Merge pull request #268082 from dominicbetts/central-export-tip

Add export tip

Author: prmerger-automator[bot]

articles/iot-central/core/troubleshooting.md

@@ -274,6 +274,10 @@ The export definition page shows information about failed connections to the exp
 
 :::image type="content" source="media/troubleshooting/export-error.png" alt-text="Screenshot that shows an example export error.":::
 
+## Data export missing data issues
+
+Data export only exports data that arrives in your application after you enable data export. If you need to export historical data or data that was missed while your data export was temporarily switched off, you can use the IoT Central REST API to query for device telemetry. Use a query to retrieve the missing data and then add the data to your export destination. To learn more, see [How to use the IoT Central REST API to query devices](howto-query-with-rest-api.md).
+
 ## Next steps
 
 If you need more help, you can contact the Azure experts on the [Microsoft Q&A and Stack Overflow forums](https://azure.microsoft.com/support/community/). Alternatively, you can file an [Azure support ticket](https://portal.azure.com/#create/Microsoft.Support).

includes/iot-central-data-export.md

@@ -20,7 +20,7 @@ For example, you can:
 - [Transform the data](../articles/iot-central/core/howto-transform-data-internally.md) streams to modify their shape and content.
 
 > [!TIP]
-> When you turn on data export, you get only the data from that moment onward. Currently, data can't be retrieved for a time when data export was off. To retain more historical data, turn on data export early.
+> When you turn on data export, you get only the data from that moment onward. To retain more historical data, turn on data export early. To manually export data from times when data export was turned off, see [How to use the IoT Central REST API to query devices](../articles/iot-central/core/howto-query-with-rest-api.md).
 
 > [!NOTE]
 > In some circumstances it could take up to 60 seconds for the messages to be exported. This time is measured from when IoT Central receives the message from the underlying IoT hub to when the message is delivered to the destination endpoint.