Fields from Blended Data Sources Unavailable for URL Actions in Tableau

Because fields from secondary data sources cannot be used in Tableau URL actions, the following workaround can assist:

• Create a new worksheet. Make the data source that contains the field that you want to use in the URL action the primary data source in the worksheet.
• Add the worksheet to a dashboard.
• Create an action filter whose source is the original worksheet and whose target is the new worksheet. For more information about creating action filters, see Filter Actions in Tableau Help. 
• Create the desired URL action with the new worksheet as the source sheet.