BigData / Tableau Interview Questions
What are the aggregate functions available in Tableau?
Aggregate functions collapse many row-level values into a single summarized value, and are the default behavior applied to every measure dropped onto a shelf.
| Function | Purpose |
| SUM | Total of all values. |
| AVG | Arithmetic mean of all values. |
| MEDIAN | Middle value, less skewed by outliers than AVG. |
| COUNT / COUNTD | Number of records / number of distinct values. |
| MIN / MAX | Smallest / largest value. |
| STDEV / VAR | Standard deviation / variance. |
SUM([Sales]) COUNTD([Customer ID]) -- unique customer count, not total rows AVG([Discount])
By default, every measure dragged into a view is wrapped in an aggregate function (usually SUM), which is why measure pills often show as SUM(Sales) rather than just Sales. Changing which aggregate is applied is as simple as right-clicking the pill and choosing "Measure (Sum)" -> a different function from the list.
Which function counts the number of unique values rather than total rows?
What is the default aggregation Tableau typically applies to a measure dropped onto a shelf?
More Related questions...
