Coming in Tableau 10 will be the inclusion of cross data-source filtering. Check out some of the FAQ's you may have, here:
Q: I have several data sources that contain product names. But each contains a slightly different list. Can I have a filter that unions all the product names together into one master list?
A: Right now, cross data source filtering uses the filter's data source to determine the domain or range of members to filter over. For members not included in the domain, the filter will exclude those values from visualization, even when “All” is selected as the value of the filter. If you require a master domain, it's best to union your dimension table separately and use it as the filter’s source.
Q: How do I map a field in one data source to a field in another?
A: Cross data source filters use relationships to map the filtering fields. You can use Automatic or Custom relationships in the Data > Edit Relationships dialog to control your relationships.
Q: Does this work with quantitative dimensions?
A: Yes. In addition to categorical dimensions, we support filtering of quantitative dimensions as well. Basically. You can filter most things you can create a relationship to.
Q: What about groups or sets?
A: Cross data source filters can be mapped to ad hoc groups so long as the filter is in a relationship to the group and members match. Groups, however, cannot serve as the filter field for a cross data source filter yet. Note that domain values are matched based on the group name rather than the individual items in the group. Sets, unfortunately, are not supported yet.
Q: I created a cross data source filter, but I'm not seeing it applied to my secondary data sources.
A: For the first version of cross data source filtering, secondary filters are not filtered. But it’s something we’re looking at.
Q: I have a fact table and dimension table that share the key ID. Can I filter using product name and have the membership pass through the key instead?
A: Unfortunately, no. We currently do not support this behavior. But I like the idea!
Q: Does cross data source filtering work with multidimensional cubes?
A: Unfortunately, we do not support cubes sources at this time.
Q: I have a cross data source filter and it's showing me an orange link icon. Am I blending?
A: No. The blending icon indicates the potential to link on a field. Blending will only occur if you drag a secondary dimension or measure onto the viz as something other than a cross data source filter.
To learn more about this feature, check out this blog post by Frankie Liu - https://www.tableau.com/about/blog/2016/5/requested-you-can-filter-across-data-sources-tableau-10-54330
EDIT: Since I can't find a Reply option to this, and I have edit powers I just want to add a prediction:
- When 10 is released this will become one of the most often referred to links on our forums
- Cross-data-source filtering will be the most often asked question on our forums
PS: Thanks Tracy for starting this post! I hope blending, data source gurus will help you flesh this out.
PPS: To help Shawn's prediction I added some tags ~Toby