Calculating time passed

You can easily calculate the time passed from a baseline date using a family of functions similar to the following one. This function returns the time in months from the baseline date to the date represented by the date string DATE as a real number. This is an approximate figure, based on a month of 30.0 days.

date_in_months(Date)

Comparing date/time values

Values of date/time fields can be compared across records using functions similar to the following one. This function returns a value of true if the date string DATE1 represents a date prior to that represented by the date string DATE2. Otherwise, this function returns a value of 0.

date_before(Date1, Date2)

Calculating differences

You can also calculate the difference between two times and two dates using functions, such as:

date_weeks_difference(Date1, Date2) 

This function returns the time in weeks from the date represented by the date string DATE1 to the date represented by the date string DATE2 as a real number. This is based on a week of 7.0 days. If DATE2 is prior to DATE1, this function returns a negative number.

Today's date

The current date can be added to the data set using the function @TODAY. Today's date is added as a string to the specified field or new field using the date format selected in the stream properties dialog box. See Date and time functions for more information.