Are these data sources being joined or blended in any way? I ask because by joining the sources, you could create one data source that only includes IDs that exist in both sources.
If you understand joins, but are working with two separate sources in Tableau for a specific reason, you can easily write a calculation like the one in my screenshot below. I've circled where you can choose your data sources from, so you can select fields from both. Note that I had to wrap my field names in the ATTR() function in order to make this work in Tableau ("cannot mix aggregates and non aggregates" error will display otherwise)
Matthew, this isn't going to work if there are multiple StudentID records in the secondary data source. For instance, if a student was taking 6 classes you could end up with 6 records with the same StudentID, which will return " * ".
Yes, this is true and thanks. I imagine what the OP wants is to join or blend but I am not sure.
My main dataset is our sales table, which has many rows for the same ID. I would like to exclude people from this project if their customerID exists in my exclusion table, which I have left joined to the sales table.
typically I would use SQL and flag the ID if they are in the second data source and then use that flag as exclusion criteria in the where statement.
I'm just wasn't sure how that translates over to Tableau logic.
I think Matthew's example might be the answer. I'm going to give it a shot.
Thanks so much.