1. From the main menu select Report/Select Expert.  For more information on the Select Expert click here.
2. Place the following in the Select Expert formula: Date({FIELD.EN_US}) >= DateAdd("m",-X,CurrentDate)

Formula Functions used:

Date({FIELD.EN_US}) - converts the {FIELD.EN_US} value to a date format.

DateAdd("m",-X,CurrentDate) - subtracts X number of months from the current date.

Notes on formula: This formula takes the current record date value in {FIELD.EN_US} and compares that value with a given number of months in the past from the current date.

Function Descriptions:

Date(x) - Converts x to a date type field, where x can be either a number, string, dateTime, or YYYY/MM/DD.

DateAdd(intervalType, nIntervals, startDateTime) - Adds two dates together where:

intervalType is a String expression specifying the interval of time to be added.

nIntervals is a Number or numeric expression specifying the number of intervals to be added. It can be positive (to get date-times in the future) or negative (to get date-times in the past). 

startDateTime is the DateTime value to which the intervals are to be added.

CurrentDate - Returns the current date on a report. The date is taken from your computer's internal clock.

For additional information and examples on formula functions, please go to Help, and Crystal Reports Help from within the Crystal Reports program.

Example: Date({FIELD.EN_US}) >= DateAdd("m",-3,CurrentDate)

This will compare each value of {FIELD.EN_US} with the date equivalent of 3 months prior to the current date.