Prompting in the query is poor practice. Use the form technique suggested above. That allows you to actually validate the response before passing it to the query.
Also, and even more important, in a database you are building for others, it is dangerous to run queries that the user can interact with UNLESS the query is not updateable. The point of forms is to control data entry and VALIDATE the data as it is entered. You have no control when using a query except for whatever RI you defined for the table and table level validation for each field. And since table level validation is so limited, it is almost useless, most validation will be done using forms.
Users should only interact with forms and reports. If you want to give them something to play with, export the query to a spreadsheet and let them slice and dice it there.