Compare equivalent periods in DAX
If you do not have a full month with data, comparisons such as year-over-year (YOY) might require particular filters in order to do a like for like comparison in DAX. This article describes how to write DAX expressions comparing equivalent periods, keeping corresponding number of days in the comparison.
When you create a year-over-year in DAX, you usually compare two set of dates from the calendar, regardless of the presence of data in all the days of the period. For example, consider the following year-over-year (YOY) calculation for Sales in December 2008 for a particular store.
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