Could be a difference in the number of columns between QVD1 and QVD2 as you are using Qualify and Unqualify the same column name might get renamed into a different one and thus showing null onconcatenate . Try loading the 2 QVD's without using the concatenate keyword and Qualify and Unqualify and check the result
I was trying to upload a small example (because QVD1 is almost 200MB) using those QVD files, but:
When I create the DB QVW it reads all fields as is, everything looks OK, but in my real DB the 'year' and 'month' fields appears as null when Flag is 'P'. It is a little rare that in one DB (new) works OK, but in my official does not.
I was checking all the field names when concatenate, but all necessary fields have the same name, so they should show in the final's file columns 'year' and 'month'.
I am usign in the Final DB qualify *, and unqualify (some common fields between QVDs) because I read several QVD files. My idea making those unqualified fields KEYS.
Marked line is where I can´t figure out why Año (year) and Mes (month) appear as null when flag is 'P'.
I started my Final BDconcatenating all of those QVD files, but the DB was very very...slow showing the information.