think of the query as going to google ans searching for "access sql"
it will show you a list of results,
now let's say you leave your computer on and those search results up and you walk away and go on vacation
then you come back 8 days later and look at your computer
is it possible the search results have changed ?
yes, but you won't see the changes until you refresh the web page
if you look at the page without refreshing then it will show exactly the same results as when you left, even though the results may be different
so you have to "requery"