When you update to Tableau 2020.2, you’ll see this on the data source view:
If you didn’t read the announcement from Tableau, you’ll think, “relate? what ever happened to join?”
Joins are still available in Tableau 2020.2, you just double-click to get back to the view you’re used to where you can create joins and unions:
Tableau says that relationships have mostly superseded blends. Relationships allow you to combine also avoid data duplication but are more flexible.
|Combines columns or rows?||Match on key field duplicates data?||Limitations||Tableau Documentation|
|Relationship||Combines columns||No||Relationships cannot be formed between tables from data sources published to Tableau Server or Tableau Online. Relationships also can’t be formed based on calculated fields.||Relationships|
|Join||Combines columns||Yes||Cross database joins will not work with all data sources||Joins|
|Blend||Combines columns||No||Fields from the secondary data source cannot be brought in to the view unless there is a match on the key field. This makes a blend somewhat comparable to a left join, since data from the primary data source is always brought into the view even if there is no match to the secondary source.
Blends are only able to combine two tables, a primary and secondary data source.
More information on limitations of blending here here
|Union||Combines rows||No, since unions do not use key fields.||Data sources used in the union must come from the same connection||Unions|