Tableau 10 Complete Reference

Row Level or Aggregate – why does it matter?

What if you create a calculated field named Price per Square Foot (Row Level) with the following code:

 [Price] / [Area] 

The code differs from the calculated field named Price per Square Foot (Aggregate):

SUM([Price]) / SUM([Area]) 

And here is the dramatic difference in results:

Why is there such a difference in the results? It's a result of the way the calculations are performed.

Note that the first measure in the preceding view is the SUM (Price per Square Foot (Row Level)). That's because the calculation is a Row Level calculation, so it gets calculated row-by-row and then aggregated as a measure ...