the data is changed monthly
How? by a query? A form? The updates/appends are on this data, or that place that you first got it from? If the latter, what is the nature of the source?
As the data changes and subsequently the query
This doesn't sound right if I interpret it correctly. Query design should not have to change because data changes.
If you have source data that may or may not be linked to the db (this is also unclear) you can update the target tables with an update query. If the source contains new records, you need an append query as well. But does the source contain records that are already in the target table and you don't want them to be added again?
I think you'll have to clarify much further as to what you're dealing with, what's going on and what you need.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.