I believe your interviewers were referring to Report Limit functionality in MicroStrategy reports. It's limit set on the report using Metrics and it is translated in to a Having clause in the SQL. For example, you can set the report limit with a Metric called Total Revenue > 5000. In the SQL, this limit will be translated in to a Having clause like 'having Sum(TotalRevAmt) > 5000. This can be set under Data/Report Data Options/Calculations/Report Limit.