Hello.
You can achieve that activating the "Show totals" option on the Dimension. Then the metric should have an IF statement with the Dimensionality function, that wil allow you to calculate a different metric for the Totals Row.
When Dimensionality is 0 (the totals row) your metric should calculate the Top 30, if Dimensionality is not 0 (the rest of the rows) the metric should be as normal.
It should be something like this.
- IF(Dimensionality() = 0,
Sum({<YourDimension= {"= num(Rank(Sum(YourMetric),4)) < 30"}>} YourMetric),
Sum(YourMetric)
)
Attached is an example.
Hope its helpful.
Best regards.
