The subMonth() function takes dateTimeValue and numberOfMonths as arguments. It returns the dateTimeValue after subtracting the specified number of months from it. The date-time value will be returned in the format specified in Application Settings.
This function will consider the number simply in terms of months. Therefore, the number of days being subtracted could vary for different date-time values. For example, 01-Jan-2019 to 01-Feb-2019 and 01 Feb-2019 to 01-Mar-2019 will be considered 1 month each, although the number of days in each case is different.
|<variable>||Variable which will contain the returned date-time value.||DATE-TIME|
The date-time value from which the specified number of months will be subtracted.
The date-time value can be specified without a time value, in which case 00:00:00 will be taken as the default time value.
If the hour value is specified as 24 or more, the date-time value be reset to 00:00:00. If the minutes value is specified as 60 or more, the mm:ss value will be reset to 00:00, if the seconds value is specified as 60 or more, the ss value will be reset to 00.
A runtime error will be encountered if:
Refer this help document to learn about the supported date-time formats.
The number of months to be subtracted from dateTimeValue.
A negative number will add the specified number of months to. dateTimeValue
newDate = currentDate.subMonth(1) // returns '01-Dec-2018 00:00:00' ;