Chapter 37: Adding Formulas to Power Pivot
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FIGURE 37.7
The Insert Function dialog box shows you all available DAX functions.
As you look through the list of DAX functions, you’ll notice that many of them look like
the Excel functions with which you are already familiar. Make no mistake, however; these
are not Excel functions. Where Excel functions work with cells and ranges, these DAX func-
tions are designed to work at the table and column levels.
To understand what that means, start a new calculated column on the Invoice Details
tab. Click the Formula bar, and enter a good old SUM function: =SUM([Gross Margin]).
Figure 37.8 shows the result.
FIGURE 37.8
The DAX SUM function can only sum the column as a whole.
As you can see, the SUM function sums the entire column. This is because Power Pivot and
DAX are designed to work with tables and columns. Power Pivot has no construct for cells
and ranges. It doesn’t even have column letters on its grid. Where you would normally ref-
erence a range, as in an Excel SUM function, DAX basically takes the entire column.