WHERE TOP or BOTTOM(n) OF
Similar to WHERE TOP or BOTTOM(n) IN, WHERE TOP or BOTTOM OF serves as a filter that limits the values included in the metric’s computations. Using the OF keyword (rather than IN) allows ranking of more than one metric and interprets the ranking metric as a sub-metric. This filter supports percent parameters: n%.
When you are using filters with a percentage (such as TOP(20%)), the number of the selected items is always rounded up.
For example, you want to select 20% of 21 items, and each item has a distinct value of the metric that it is ranked by. The result is going to be 5, because 20% of 21 is 4.2, and it gets rounded up to 5.
SELECT … WHERE TOP(…) OF … [WITHIN …] SELECT metric1 WHERE [TOP|BOTTOM](n) OF ( metric2 , ...) SELECT metric1 WHERE [TOP|BOTTOM](n) OF ( metric2 , ...) WITHIN ( ... )
SELECT Amount WHERE TOP(5%) OF ( Amount ) AND Product = Explorer
This may also help: