Hi all,

Glad to find this place. I'm new to Tableau Prep and trying to reproduce a data set that I used to build in Power Query.

Something strange happens when I use wildcard union as a data input. If I select Single table, sample value is shown and all following steps (join with another table, etc.) show result sets as well. However, when I select Wildcard Union, sample value is no longer there and all following result sets are just empty. (see pics below)

I have several Wildcard Union data inputs, and wield enough, one of them does work but all the other just do not perform properly. They're all csv files sitting in separate folders. I also edit the connection to select another file in the folder as a start point, still the same issue. To use all data rather than default sample amount does not make a difference. Creating a new flow to start over again does not fix the problem either.

Single Table works fine

After switching to Wildcard Union, Sample Values no longer appear

All following result sets show nothing

Could anyone suggest what's the possible issues here and how to fix it?

Appreciate in advance,

Olivia