Dynamic function to select mysql data based on date

[tdnxxx444]

I want to create a dynamic, generic function that will SELECT data from a mysql table based on various types of dates.

The dates could be in the form of:

1. No date
2. A specific date
3. A date range
4. x many months from the current date
   i.e. mysql statement - WHERE EXTRACT(YEAR_MONTH FROM date) = EXTRACT(YEAR_MONTH FROM DATE_SUB(NOW(), INTERVAL x MONTH))
5. etc -- whatever other variations

Anyone have any suggestions on the best way of accomplishing this?