Specify Mark as Date Table for use with Time Intelligence (SSAS Tabular)

In order to use time intelligence functions in DAX formulas, you must specify a date table and a unique identifier (datetime) column of the Date data type. Once a column in the date table is specified as a unique identifier, you can create relationships between columns in the date table and any fact tables.

When using time intelligence functions, the following rules apply:

• When using DAX time intelligence functions, never specify a datetime column from a fact table. Always create a separate date table in your model with at least one datetime column of Date data type and with unique values.

• Make sure your date table has a continuous date range.

• The datetime column in the date table should be at day granularity (without fractions of a day).

• You must specify a date table and a unique identifier column by using the Mark the Date Table dialog box.

• Create relationships between fact tables and columns of Date data type in the date table.