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Enable left/outer joins for Teradata-based datasource extracts using "Multiple tables" feature  [RELEASED]

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Enable left/outer joins for extracts sourced from Teradata using the Multiple tables feature.




Attached screenshot shows the optimal functionality, but it only works for Excel, not Teradata sources



  • "Multiple tables" extracts with left/outer joins is enabled and works great with Excel data sources, but not for Teradata sources (is this a bug?)
  • Enabling left outer joins enables independent/multidimensional security models to be applied
  • Current state assumes all records have joins against all the tables which isn't always the case
  • Since the "Multiple tables" option is only enabled for inner joins, the use-case is limited, or requires data explosion to ensure the inner join doesn't exclude transactions





We have to add a ton of additional processing on the database side to ensure the inner join  logic applies to our security model, causing data explosion in the security table. For example one row of data has to include all the people who have access to it in order to prevent users from being excluded from the data via the multiple inner joins.


An example of our security model for Purchase Order data:

  1. Initiators
  2. Requestors
  3. Approvers
  4. Managers
  5. Controllers
  6. Department/Org-based access
  7. Region/LOB access


If a person doesn't exist in all 7 tables above, they are excluded via the multiple inner joins. For whatever reason this is not a problem with Excel data sources, only Teradata.


What is your role in your organization?


Our team develops large, centralized Tableau data sources for broad audiences (>1,000 users) with complex, multidimensional security models from Teradata.


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