BigData / Tableau Interview Questions
What is the order of operations for filters in Tableau?
Tableau applies different filter categories in a fixed order, regardless of the order you added them in the interface. Understanding this order explains many "why doesn't my filter work the way I expected" situations.
- Extract filters (if using an extract) — limit what's even pulled into the extract.
- Data source filters — applied to every worksheet using that source.
- Context filters — run next, and define the "context" for everything after.
- Dimension filters (non-context) — standard filters on discrete fields.
- Measure filters and Sets used as filters.
- Table calculation filters — run last, since they depend on the result set already being assembled.
This ordering is why a Top-N table calculation filter that seems to "ignore" a dimension filter is usually actually working correctly — it's just evaluating the ranking after all earlier filters already ran, which is normally the desired behavior, but can surprise someone who expected filters to apply in whatever order they were dragged onto the shelf.
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