Your only way is through a series of If statements to determine the minimum.
Remember, too, that you may need to handle missing data. You can use the Nz
function in that case, but you need to be able to assign a reasonable value
for comparison purposes if the value is Null.
Dim lngMinimum As Long
lngMinimum = Nz(Me.Field1, 9999)
If Nz(Me.Field2, 9999) < lngMinimum Then
lngMinimum = Me.Field2
End If
If Nz(Me.Field3, 9999) < lngMinimum Then
lngMinimum = Me.Field3
End If
If Nz(Me.Field4, 9999) < lngMinimum Then
lngMinimum = Me.Field4
End If
If Nz(Me.Field5, 9999) < lngMinimum Then
lngMinimum = Me.Field5
End If
If Nz(Me.Field6, 9999) < lngMinimum Then
lngMinimum = Me.Field6
End If
If Nz(Me.Field7, 9999) < lngMinimum Then
lngMinimum = Me.Field7
End If
If Nz(Me.Field8, 9999) < lngMinimum Then
lngMinimum = Me.Field8
End If
(The reason you don't need to use Nz when assigning a value to lngMinimum is
that you know the field's value isn't Null inside each If statement)