User Guide

DateDiff 445

DateDiff

Description

Determines the integer number of units by which date1 is less than date2.

Returns

A number of units, of type datepart.

See also

DateAdd, DatePart, CreateTimeSpan

History

ColdFusion MX:

• Changed how negative date differences are calculated: this function calculates negative date

differences correctly; its output may be different from that in earlier releases.

• Changed the w and ww attributes; they determine the number of full weeks between the two

dates.

Parameters

Usage

The DateDiff function determines the number of complete datepart units between the two

dates; for example, if the datepart parameter is "m" and the dates differ by 55 days, the function

returns 1.

Enclose string constant dates in quotation marks. If the text contains only numbers (such 1932),

and is not surrounded by quotation marks, ColdFusion interprets it as a date/time object,

resulting in an incorrect value.

Parameter Description

datepart String specifying the units in which to count; for example yyyy requests a date

difference in whole years.

• yyyy: Years

• q: Quarters

• m: Months

• y: Days of year (same as d)

• d: Days

• w: Weekdays (same as ww)

• ww: Weeks

• h: Hours

• n: Minutes

• s: Seconds

date1 Date/time object, in the range 100 AD–9999 AD.

date2 Date/time object, in the range 100 AD–9999 AD.