Help regarding finding out maximum value from the records entered by form

[rushitshah]

Hi People,
I am working on a database related application in which the user enters the data from the form and it is stored in 3 related tables in DB.

This is what I want to do,

If IsNull(Me.Q1_2005) = True Or Me.Q1_2005 = "" Then
rs!January2005 = Me.Jan_05
rs!February2005 = Me.Feb_05
rs!March2005 = Me.Mar_05
If parametername = "time" then
rs!Q12005 = DMax([Me.Jan_05], [Me.Feb_05], [Me.Mar-05])
else
rs!Q12005 = DMin([Me.Jan_05], [Me.Feb_05], [Me.Mar-05])
End If

If user enters monthly data of Jan'05, Feb'05 and Mar'05, but he is not entering quarterly data of 2005 Q1. So I need to update Q1 data in that record, that has a condition. If the parameter name is time then I want maximum of the three month data assigned to Q1 record in DB table else I want minimum of those three text box values assigned to Q1 record in DB table.

Please help me with this kind of conditional statement.

Rushit..