[Mary Bezanson]

I ran a query for a mailing list, with the criteria of last gift given between to dates. I got multiple entries for the companies. Other times I've done this the name of the company does show, just the address.

[Melissa Siobhan]

What type of query is this - a consittuent query or a gift query?
What fields were included in the output of your query?

Query is not a reporting or exporting tool - it is simply a grouping tool. Once you have the criteria entered you need not even put anything in output - most people do just so they can check that the results came out as expected - but it will not effect the final fields included when you use Mail or Export. To get your final data you will need to use either Mail or Export - there you will only get one record per constituent and if you export org name it should not be blank.