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DateAdd

add or subtract a specified number of days, months, quarters, or years to a date.

The DateAdd function in Power FX is used to add or subtract a specified number of days, months, quarters, or years to a date. This function is useful when you need to calculate future or past dates based on a starting point.

Syntax

The basic syntax is:

DateAdd(ThisItem.DateTimeColumn, AddedValue, TimeUnit.[Unit])

However, your DateTime data in the Alloy table is always ISO 8601 formatted. Therefore, you need to use the DateValue() or DateTimeValue() function to convert an ISO 8601 formatted date string to a valid date type that Power FX can work with.

Then, the syntax will be:

  • If the data includes Date only

DateAdd(DateValue(ThisItem.DateTimeColumn), AddedValue, TimeUnit.[Unit])

  • If the data includes Date and Time

DateAdd(DateTimeValue(ThisItem.DateTimeColumn), AddedValue, TimeUnit.[Unit])

The result will be formatted as Date(year, month, day). To covert it back to 8601 ISO format use Text().

The complete syntax

  • If the data includes Date only

Text(DateAdd(DateValue(ThisItem.DateTimeColumn), AddedValue, TimeUnit.[Unit]),"yyyy-MM-dd")

  • If the data includes Date and Time

Text(DateAdd(DateTimeValue(ThisItem.DateTimeColumn), AddedValue, TimeUnit.[Unit]),"yyyy-MM-dd hh:mm:ss")

In which:

ThisItem.DateTimeColumn: Column of Date Time data for the start date

AddedValue: Number, in Units, to add to the DateTimeColumnYou can use a negative number to subtract time.

TimeUnit.[Unit] - Optional. The type of Units to subtract or add including TimeUnit.Milliseconds, TimeUnit.Seconds, TimeUnit.Minutes, TimeUnit.Hours, TimeUnit.Days, TimeUnit.Months, TimeUnit.Quarters, or TimeUnit.Years. If not specified, TimeUnit.Days are used.

Example

Table

You have a table to track your tasks with columns StartDate and Duration(days).

Requirement

Calculate the Expected End Date = Start Date + Expected Duration (Days)

Formula

Text(DateAdd(DateValue(ThisItem.StartDate), ThisItem.'Duration(days)', TimeUnit.Days),"yyyy-MM-dd")

Result

If the formula and data are correct, you can see the value of the column when you set it to view it in the app.

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