DAX Function Guide

The PREVIOUSMONTH function (DAX) returns a table that contains a column of all dates from the previous month, based on the first date in the dates column, in the current context.

This function returns all dates from the previous month, using the first date in the column used as input. For example, if the first date in the dates argument refers to June 10, 2009, this function returns all dates for the month of May 2009.

The dates argument can be any of the following:

• A reference to a date/time column.
• A table expression that returns a single column of date/time values.
• A Boolean expression that defines a single-column table of date/time values.

Constraints on Boolean expressions −

• The expression cannot reference a calculated field.
• The expression cannot use CALCULATE function.
• The expression cannot use any function that scans a table or returns a table, including aggregation functions.

However, a Boolean expression can use any function that looks up a single value, or that calculates a scalar value.