Anyone good with Joins?

Hi,

I'm thinking that this should be an outer join, but I am looking for some decent examples.

In this query, the conditions are the same. However, the second query contains one extra table/condition/column not in the first query. Right now I am getting duplicates which would be the result of both queries........

Any thoughts? If I find a good example searching the net it'd be great. but I thought I'd also ask some of the experts here.

Thank you,

SELECT TO_CHAR(co.date_entered, 'DD-MON-RRRR HH:MI:SS AM') date_entered, p.subproduct_id, p.code,

       p.price, co.customer_id, ol.status, co.confirm, NULL adid FROM customer_order co, order_line ol, product p WHERE co.order_id = ol.order_id AND ol.product_id = p.product_id   AND co.date_entered >= TRUNC(SYSDATE) - 7 AND p.subproduct_id IN   (SELECT newsletter_id FROM product_group) UNION
SELECT TO_CHAR(co.date_entered, 'DD-MON-RRRR HH:MI:SS AM') date_entered, p.subproduct_id, p.code,

       p.price, co.customer_id, ol.status, co.confirm, ss.adid FROM customer_order co, order_line ol, product p, data_holder.shopcart_sessions ss
WHERE co.order_id = ol.order_id AND ol.product_id = p.product_id   AND ol.order_id = ss.order_id AND co.date_entered >= TRUNC(SYSDATE) - 7 AND p.subproduct_id IN

    (SELECT newsletter_id FROM product_group) ORDER BY date_entered DESC; Received on Wed Apr 09 2008 - 10:28:18 CDT