[EpiData-list] Question re defining a new variable in EpiData Analysis

Hello,

I am a relatively new EpiData user and am now using EpiData Analysis.

In EpiData Analysis I would like to create a new variable which will be the number of days between two dates which I have collected in my EpiData dataset. I have started with "define" and the name of the new variable and the new variable will be a numeric variable of length 4. i.e:

define smeartoreg1 ####

However, I am having difficulty with the code for defining the number of days between two existing dates and would appreciate some advice on this. I think I am making a simple mistake that can easily be fixed.

Many thanks.

Kind regards, Kerri