MS Access has limited capabilities to manage raw SQL queries: the editor is quite bad, no syntax highlighting, it reformats your raw SQL into a long string and you can't insert comments.
Debugging complex SQL queries is a pain as well: either you have to split it into many smaller queries that become difficult to manage when your schema changes or you end-up with a giant query that is a nightmare to debug and update.
How do you manage your complex SQL queries in MS Access and how do you debug them?
At the moment, I'm mostly just using Notepad++ for some syntax colouring and SQL Pretty Printer for reformatting sensibly the raw SQL from Access.
Using an external repository is useful but keeping there's always the risk of getting the two versions out of sync and you still have to remove comments before trying the query in Access...