Hi everyone. First of all, I'd like to thank you in advanced for your help, and apoligize for my bad English.

Let me explain my situation. I attach an example of my solution.

I have my clients, with an ID number ('CUIT/CUIL'), and one date field called 'Cierre de ejercicio'.

I also have a table ('base_d_impuestos') in which each record ('impuesto 1' , 'impuesto 2', 'impuesto 3', etc) has different dates ('january 1', "january 2", "january 3"; "february 1", "february 2", etc) that I'll have to choose according to the two fields of my clients.

I mean: when I create a record in the layout "Impuestos", called 'impuesto 1', and the 'cuit/cuil' of my related client is last number is <3, and month('Cierre de ejercicio')=1, I have to choose the date "january 1".

If the field I create is "impuesto 1", and the 'cuit/cuil' of my related client islast number is >3 and <5, and month('Cierre de ejercicio')=1, I have to choose the date "january 2".

If the field I create is "impuesto 1", and the 'cuit/cuil' of my related client is last number is >6 and <9, and month('Cierre de ejercicio')=2, I have to choose the date "February 2".

How would I have to set my calculation? Please let me know if you can't understand anything of my explanation.

 

PS: I can't attach the file, but you can download it from here https://docs.google.com/open?id=0B3Zo_cOryTdVMGtKaUQ2UGpiYVk

Sorry, but I don't quite understand whether you have a well defined mathematical relationship between 'cuit/cuil' and the calculated date.  

 

If this is something that is not precisely defined or might change from year to year, then you might want to create a separate hash table that contains 9 records (cuit 0 - 9) and lists the corresponding date in a second field. 'Base_d_impuestos', or any other table can use this to calculate the date based on a relationship that keys on the Cuit field.