Query Assistance

First time poster, so I hope someone shows me the light and makes your forums shine! :)

I have a POS system that was designed in house which uses Access. I am trying to create some queries outside of the system to retrieve some data that has been being stored. I am basically wanting to know which items have been in stock for over 6 months and have never sold.

I have a query designed to show me this data for one store at a time, but nothing that shows me if an item is so poor it has never sold at any stores. This is my single store query:

SELECT Inventory_ProductTable.Artist, Inventory_ProductTable.Title, Inventory_ProductTable.Quantity, Inventory_ProductTable.Category2
FROM Inventory_ProductTable
WHERE (((Inventory_ProductTable.Quantity)>0) AND ((Inventory_ProductTable.LastBuyDate)<Date()-"180") AND ((Inventory_ProductTable.masterStoreID)="CDT001") AND ((Inventory_ProductTable.DepartmentID)=1) AND ((Inventory_ProductTable.LastSaleDate)=""));


It is pulling the artist, title and category of the item out of the database to display the informtion that I am needing (for the most part). Quantity of 0 and last sale date "" basically means there is no record of it being sold, so this gives me my zero quantity sold criteria for anthing that has been in stock for 6 months or more (the last buy date criteria).

I am not sure what other info I need to provide, but I would be happy to do so. I am a n00b at this and really love to learn, so lay it on me!

thanks in advance.