Question

im developing a simple access application that helps us to order the right products for a project. i have a table for each contractor containing its products. i have a table “favorite-products” that relates to products and gives additional information how and when they should be used.

normally id have a big table (containing all products) that has a contractor-column. i my favorite-products table i could then easyly relate to a product. but here i need to keep the products in separate tables. so whats the best way to connect my favorite-products table with the products in the contractor-tables?

thanks 🙂

Answer 1

This is not the best design.

You should UNION all contractor tables together and JOIN with the result:

SELECT  *
FROM    (
        SELECT  product
        FROM    contractor1
        UNION ALL
        SELECT  product 
        FROM    contractor2
        UNION ALL
        …
        ) c
JOIN    favorite f
ON      f.product = c.product

You better keep one single table for you products with contractor as a field.

It will be much easier to query and to manage.