# op:subtract-yearMonthDuration-from-dateTime

Subtracts the time duration specified by $yearMonthDuration-var from the date and time specified by $dateTime-var.

### Signatures

op:subtract-yearMonthDuration-from-dateTime(xs:dateTime $dateTime-var, xf:yearMonthDuration $yearMonthDuration-var) —> xs:dateTime

### Arguments

Data Type | Argument | Description
--- | --- | ---
xs:dateTime | $dateTime-var | Contains a representation of the date and time.
xf:yearMonthDuration | $yearMonthDuration-var | Contains a time duration which can contain years and months.

### Returns

Returns the dateTime value of subtracting the time duration specified by $yearMonthDuration-var from the date and time specified by $dateTime-var.

### Examples

#### Subtracting a Positive yearMonthDuration

The following example query subtracts a positive yearMonthDuration value equal to 1 year and 1 month from a dateTime value equal to the date: February 2, 2003 and time: 1:01 AM as shown in the following query:

    <positive>{
    	op:subtract-yearMonthDuration-from-dateTime(xs:dateTime("2003-02-02T01:01:00"), xf:yearMonthDuration("P1Y1M"))
    }</positive>

The resulting dateTime value equal to the date: January 2, 2002 and time: 1:01 AM is returned as shown in the following result:

    <positive>2002-01-02T01:01:00</positive>

#### Subtracting a Negative yearMonthDuration

The following example query subtracts a negative yearMonthDuration value equal to 1 year and 1 month from a dateTime value equal to the date: January 2, 2003 and time: 1:01 AM as shown in the following query:

    <negative>{
    	op:subtract-yearMonthDuration-from-dateTime(xs:dateTime("2003-01-02T01:01:00"), xf:yearMonthDuration("-P1Y1M"))
    }</negative>

The resulting dateTime value equal to the date: February 2, 2004 and time: 1:01 AM is returned as shown in the following result:

    <negative>2004-02-02T01:01:00</negative>

Related Topics

W3C subtract-yearMonthDuration-from-dateTime operator description.

W3C yearMonthDuration description.

xf:yearMonthDuration constructor description.

W3C dateTime data type description

xs:dateTime constructor description.