Folks, What is the best way to configure AF analyses (rollup or expression) to find top 3 values of an attribute from child elements (bulk number of child elements)? Similar to finding maximum value using rollup on child element.
Similar like this one: Re: Rollup Analysis of Attribute With Matching Values you could try and create the first rollup for the top 1, read the top 1 value in each child element to filterthe value if these is a top 2 candidate, and repeat...
The same idea is shown in the RollUp section of the document referenced here: Tips and Tricks for Asset Based Analytics
A whole different approach would be to use an OLEDB Enterprise loopback query: Displaying Top N Elements
Although the latter works, it is tricky and messy in many ways.
Of course, a Custom DataReference is always an option, but only if you know what that is. Custom DRs are 'restricted technology' for a reason.
May I ask what your use case for this would be? Also, let's say that this functionality existed. How would you store the results? 3 events in the same PIPoint, or 3 events in three different PIPoints?
It is to know the top 3 performing (or non-performing) assets. Also, we should be able to get the element names of the top 3 child elements. The results would be stored in different attributes and will be displayed using PI client tools.
Retrieving data ...