Sometimes, you might want to connect to data in an external location, like an Access/SQL Server table, an XML file, the web, or a text file. Unfortunately, you can’t do that in Excel Online.
However, you can open a workbook that already has data connected to external locations, and refresh that data in Excel Online by clicking Data and choosing one of the refresh options.
If you have the Excel desktop application, you can use it to open your workbook to create a data connection. Here’s how:
Click Open in Excel and follow the steps in Connect external data to your workbook.
When you save the workbook and reopen it in Excel Online, you'll see the changes you made.
For news about the latest Excel Online updates, visit the Microsoft Excel blog.