Date.IsInPreviousDay

Date.IsInPreviousDay is a Power Query M function that indicates whether the given date(time) value occurs during the previous day, as determined by the system. The function returns a boolean value (true or false).

Compatible with: Power BI Service Power BI Desktop Excel Microsoft 365

Syntax

Date.IsInPreviousDay( dateTime as any ) as nullable logical

Description

Date.IsInPreviousDay determines if a given value (of type date, datetime, or datetimezone) occurs during the previous day, based on the current system date and time. Returns false for values within the current day.

Examples

Let’s explore two straightforward examples to understand how the Date.IsInPreviousDay function works.

Identifying the Previous Day in a Calendar Table

Suppose you have a calendar table and you want to add a column that indicates true for dates that fall on the previous day. You can do this using the Date.IsInPreviousDay function on your [Date] column.

Date.IsInPreviousDay( [Date] ) // Output depends on [Date] column

This expression returns true for any date in the [Date] column that falls on the previous day.

For example, if today is July 6, 2024, this function will return true for all rows with dates of July 5, 2024. Here’s a screenshot showing this:

You can see that the previous day, July 5, 2024, is marked with true.

Using the Current Date and Time

To check if the date and time from the previous day falls within the previous day, you can use the following expression:

// Output: true
Date.IsInPreviousDay( Date.AddDays( DateTime.FixedLocalNow(), -1 ) )

Related functions

Other functions related to Date.IsInPreviousDay are:

• Date.IsInPreviousMonth
• Date.IsInPreviousQuarter
• Date.IsInPreviousWeek
• Date.IsInPreviousYear

Contribute » | Contributors: Rick de Groot
Microsoft documentation: https://learn.microsoft.com/en-us/powerquery-m/date-isinpreviousday