Data blending in Tableau uses a left outer join relationship by default, where all records from the primary data source are preserved and only matching records from secondary sources are included.
Practical Response 1:
“Data blending in Tableau functions like a left outer join—it keeps all my primary data and pulls in matching information from secondary sources, automatically handling the relationships behind the scenes.”
Practical Response 2:
“When I use data blending in Tableau, it creates left join logic between my data sources. This means I get all records from my main dataset and only the matching records from my secondary sources.”
Detailed Explanation:
Data blending in Tableau operates on a left outer join principle, though it doesn’t use traditional SQL join syntax. Instead, Tableau establishes relationships through linked fields that act like primary and foreign keys. The primary data source (marked with a blue checkmark) determines the base dataset, while secondary sources (orange checkmarks) contribute matching records based on common dimensions.
Unlike database joins that combine data at the row level before aggregation, data blending in Tableau aggregates measures within each data source first, then combines the results. You can emulate different join types by changing which data source is primary or by applying filters to remove non-matching records.
Keywords:
- data blending Tableau
- left outer join Tableau
- primary data source Tableau
- secondary data sources
- data blending relationships
Which join is used in data blending?.