> ## Documentation Index
> Fetch the complete documentation index at: https://www.integrate.io/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# ETL: SubtractDuration

> Subtract a duration string expression from a datetime value and return the result. Use SUBTRACTDURATION for date arithmetic in ETL data pipelines.

## Description

Returns the result of a datetime\_expression minus a duration string expression.

## Syntax

`SubtractDuration(datetime_expression, duration)`

## Arguments

*datetime\_expression* - datetime expression.

*duration* - duration string in ISO 8601 format. See [https://en.wikipedia.org/wiki/ISO\_8601#Durations](https://en.wikipedia.org/wiki/ISO_8601#Durations)

## Examples

`SubtractDuration(ToDate('2013-09-10T08:02:31.667Z'),'PT3H')` returns '2013-09-10T05:02:31.667Z'

## Return value datatype

DateTime

## Impact of null value

If input is null, returns null.