Next, you are going to determine the age of each customer. The Customer table currently contains a column with the birth date for each customer. This column, along with the TODAY function and some DAX, will allow you to determine each customer's age. Your first attempt at this calculation may be to use the DATEDIFF function in a calculation that looks something like the following:
Customer Age = DATEDIFF('Customer'[Birth Date], TODAY(), YEAR)
The TODAY function returns the current date and time. The DATEDIFF function returns the count of the specified interval between two dates; however, it does not look at the day and month, and therefore does not always return the correct age for each customer.
Let's rewrite the previous ...
