compare a field in end routine of different lengths

Hi,

I am writing an end routine where I want to compare sales doc in VBAK with the object ket field in NAST.  From this I want to return the date field.  The issue is sales doc is length 10 and object key is 30.

Because I am reading the result_package it doesn't look like I can assign a temp field before the select staement.  Is there something else I can do?  or do I read in the table then do the compare.

Thanks

Denise