Forum Discussion
PBRS March Update breaking existing RDL reports that use LOOKUP function
The changelog should be updated soon but to answer your question yes this build addresses the nested Lookup function expression errors as well as several other bug fixes.
I just wanted to confirm that the latest build:
Version 1.2.6690.34729 (Build 15.0.2.402)
Does indeed fix the issues we were having. At this point, we are going to be moving this to our produciton instances, as it has passed all of our internal regressions.
mgmeyerwrote:Thanks for reporting the issue this is something we are looking into. One question for you, are you using the Lookup function in the Header/Footer of the report or is it on the main canvas? How many reports do you have that are impacted by this? We do have one possible work, you can create a report level variable that contains the Lookup function and then reference that in your nested expression.
The lookup function is in the tablix on the main canvas.
In total, we have 10 reports that are impacted.
As for the variable, I don't think that solution will work. Right now, we have the lookup being using in a column on a tablix. So it is repeated for each row. If I try and use a variable, I get the following error:
The Variable(LookUpTest1) expression for the report 'body' refers diorectly to the field 'Year_and_Month_and_Group' without specifing a dataset aggregate. When the report contains multiple datasets, field references outside of a data region must be contained within aggregate functions which specify a dataset scope.
In my case I don't think I can perfrom any aggregates, as the data is row level.
mgmeyer, it looks like there are some more bugs we have identified with the RDL/Paginated reports in this latest March update of Power BI Report Server
When we use an aggregate function in a page footer, we get an #Error message on the new version. On the old October version this worked fine.
Code example:
="Market(s): " + IIF(Parameters!P_MA.Count = Sum(Fields!ParameterLevel.Value, "P_MA_Param"), "All", Join(Parameters!P_MA.Label, ", "))
We were able to work around using a variable:
="Market(s): " + IIF(Parameters!P_MA.Count = Variables!MarketAll.Value, "All", Join(Parameters!P_MA.Label, ", "))
But if we need to update all reports for this bug, it becomes an issue. Were there some regressions that got missed when building this new release? Looking at the change log, there isn't a lot of changes to the RDL/Paginated reports, so it is surprising to find so many breaking issues.
Thanks Ben for the update, we are actively looking into the issue and hope to have a fix soon. To your question around changes there we changes that do impact RDL reports however most of the them were infrastructure related.
- Awesome.
If there are any log files, or stack trace files, that I can send let me know. More than willing to help out troubleshoot. 
Is this a general issue. In other words: the "Lookup" functions don't work at all in this PBRIS March 2018 release.
My customer has some 15 reports using this kind of functionality.
Hard to say.
I have many reports that use lookup. Some of them have no issues. Some of them have issues. I can't exactly tell what causes the #Error, but it seems like if the lookup is used in conjunction with anything else, it fails.
Best thing I can say to do is test it out. Install the update on a test instance, and load up your RDL files. Initialy, our plan was to spot check reports, since it didn't seem like there was any real changes around RDL reports in this release. But seeing as how we have found these breaking issues, we are going through the process of evaluating all 180 reports we have on our system.