Formula to find value between dates

[#1]

HI,

Say, for instance, I had the following values:

DOC NUMBER:     DELIVERY NUMBER:     [CREATED ON]:     [PICKING DATE]:   

  124578                    A124578                         2012.06.01          2012.06.01    

                                B124578                          2012.06.01          2012.06.03

What kind of formula would I use to calculate the number of days the DOC_NUMBER takes to process inbetween [Created on] date and [Picking date]?

In this case I would looking for the value 2.

Any help would be greatly appreciated

Thanks

[fosuzuki]

How about:

max([Picking Date]) - min(Created On])