question regarding aggregation

[Former Member]

Hi Guru:

I have a question for the aggregation in calculation view.

For the calculated columns in the aggregation pattern, are they calculated after aggregation or before aggregation?

I need to do a A/B for the aggregated result, want to see whether I can use the calculated column or need to create another step.

Thanks a lot.

Eric

[rindia]

Hi Eric,

In the properties check for the option "Calculate Before Aggregation".

If it is selected then calculation happens as per the expression specified and then the results are aggregated.

If it is NOT selected the calculation happens as per the expression specified but the data is not aggregated but shown as formula.

Regards

Raj

[Former Member]

My suggestion - try it out. Create a small table of a couple columns and couple records, and do a simple multiplication. Check the results and see if it's calculated before or after aggregation.

One thing to keep an eye on - calculated measures in Analytic View. There is a checkbox 'Calculate before Aggregation'. This will slow performance, and will only work if expression definition doesn't include dimensions*. (Considered generated columns in this column when possible).

*if dimensions are included in the calculated measure definition, you'll receive a warning telling you that 'Calculate before Aggregation' will be ignored. The reason is that such expressions are evaluated by the CalcEngine, which processes calculation after OLAP Engine processing (i.e. aggregation).