Current versus prior and growth rates

With date intelligence measures developed for the current and prior periods, growth or variance measures can be added to the dataset, comparing the two values. In the following example, a year-over-year (YOY) and a year-over-year year-to-date (YOY YTD) measure have been created based on the current year and prior year measures from the preceding section:

Internet Net Sales (YOY) = [Internet Net Sales (CY)] - [Internet Net Sales (PY)] 
Internet Net Sales (YOY YTD) = [Internet Net Sales (YTD)] - [Internet Net Sales (PY YTD)] 

Finally, growth percentage measures can be added, which express the variance between the current and prior period measures as a percentage of the prior period. The following measures reference the above YOY measures as the numerator within a DIVIDE() function:

Internet Net Sales (YOY %) = DIVIDE([Internet Net Sales (YOY)],[Internet Net Sales (PY)]) 
Internet Net Sales (YOY YTD %) = DIVIDE([Internet Net Sales (YOY YTD)],[Internet Net Sales (PY YTD)])

The DIVIDE() function returns a blank value if the denominator is zero or a blank value by default. The divide operator (/), however, will return an infinity value when dividing by zero or a blank. Given the superior error-handling behavior and performance advantages of DIVIDE(), the DIVIDE() function is recommended for computing division in DAX.