I have 2 lists (databases) and I would like to see another database with the
resulting from their combination (i.e. if both lists have the word "apples"
then I would like to see only one word: "apples" with the corresponding sum
from both lists like quantities and, of course, the rest of the items). The
problem is that I do not know exactly what's going to be in each list. They
may vary. Please help.