Need Help with Advanced SQL Query

Question

It's advanced for me, at least. I have three tables that I
need to use:
Product (product_id and product_title are the fields)
shipRegion (shipRegion_ID)
product_shipRegion_shipCharge (product_id, shipRegion_ID,
primaryShipCharge, secondaryShipCharge)
What I am trying to do is create a query that will look for
two things:
1. Any product that is listed in the
product_shipRegion_shipCharge table that has a primary or secondary
ship charge of $0.00 or is NULL.
That part is easy:
SELECT DISTINCT p.product_id, p.product_title
FROM product p
INNER JOIN product_shipRegion_shipCharge pss ON p.product_id
= pss.product_id AND (pss.primaryShipCharge IS NULL OR
pss.primaryShipCharge = 0 OR pss.secondaryShipCharge IS NULL OR
pss.secondaryShipCharge = 0)
WHERE p.display = 1
AND p.price > 0
It's this next part that's tricky for me:
2. Get the product_id and product_title (from the product
table) that does NOT have any entry in the
product_shipRegion_shipCharge table.
I'm guessing that I need to include some kind of LEFT JOIN in
the above query to find out what all of the regions are (from the
shipRegion table) and then see what's missing for each product in
the product_shipRegion_shipCharge table, but I have no idea how to
do it.
Anyone?
Josh

Answer 1

This should be what the query would look like using the left
join:
SELECT product_table.product_id, product_table.product_title
FROM product_table
LEFT OUTER JOIN product_shipRegion_shipCharge
ON product_shipRegion_shipCharge.product_id =
product_table.product_id
WHERE product_shipRegion_shipCharge. product_id IS NULL
SQL Server's query optimizer will probably turn the '...IN
(subquery)' or '...exists (subquery)' into this kind of execution
plan on its own - depending on your table structures.