View the original community article here
Last tested; Feb 1, 2021
You may notice that when you select the week dimension and some other fields, your data looks alright!
However, when you add in your month dimension, some of your week rows are duplicating!
Why is this happening? In this case, we can see 2020-12-28 getting repeated. This is because this week starts in the month 2021-012 and ends in 2021-01. There are two of the same week values, but they're getting correlated to two different months, causing the duplication.
How can we fix it? We can add in a table calculation to extract the month. This will correlate the week to the month it starts in.