How to automatically refresh external data in Excel 2011 on OS X?
Refreshing a data table in your Excel workbook

If your query table is linked to a data source, you can update the data in your workbook on demand so that it reflects the current state of the data source. On the Ribbon’s Data tab, go to the External Data Sources group and click Refresh button’s triangle to display a pop-up menu, where you can choose from the options.