Tableau Server data sources are powerful tools for sharing data connections among multiple authors and workbooks. Tableau Sever data sources can contain everything a user needs to connect to data and start authoring workbooks, such as any required database drivers and field level customizations. However, field-level customizations like custom calculations that blend two Tableau Server data sources together will not work if the data source containing the calculated field is published to Tableau Server. This is because information about the blended data is saved with a workbook, and not with the data source.
Therefore, if you need to use a calculation that blends two Tableau Server data sources together, Tableau recommends publishing the data sources to Tableau Server first, adding the calculated fields that you need, and publishing the workbook to Tableau Server as a “template”. This "template" can then be shared and downloaded by users. This general process is described below.
Step 1
Open Tableau Desktop, and create a live connection to each data source that you want to blend, and then publish each connection to Tableau Server.Step 2
Create a new workbook, and connect to each data source you published in step 1.Step 3
Select Data > Edit Relationships to define a relationship between fields in the data sources. This will allow you to blend data from both data sources on a single sheet.Step 4
Create the desired calculated fields that blend the data sources.Step 5
Add a field to the view. For example, Number of Records. You must have at least one field in the view to publish the workbook.Step 6
Save and publish the workbook to Tableau Server.Users can now download this workbook as a “template” to begin their analysis, and use the blending custom calculation it contains.