DAX users in Power bi tend always to do the same mistake, They apply Time Intelligence Functions “TIF” on a column dates that contain duplicate dates or gaps. Wrong, very wrong!
If the date column in your model contains duplicate dates then TIF will return an error
and if there is gaps in it then TIF will not return the most accurate result and can induce the user into false analysis.
Therefore the best practice to avoid mistakes in your model and your calculations using TIF is to add a Calendar Table(dimension Table) and join it with the column date from the fact table.
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