Varius

Is this possible? (LEFT JOIN question)
I have two tables, I'll simplify them for the sake of this example:

table1:
campaign_id int unsigned not null default 0 key

table2:
month tinyint not null default 0 key
year smallint not null default 0 key
campaign_id int unsigned not null default 0 key
revenue double(5,2) not null default 0.00

What I"m trying to achieve is to get all the campaign_ids from table1, regardless of if they have a row in table2 or not.

This part I'm getting with:

"SELECT t1.campaign_id, t2.revenue FROM table1 t1 LEFT JOIN table2 t2 ON t1.campaign_id=t2.campaign_id WHERE (t2.campaign_id IS NULL OR t2.campaign_id IS NOT NULL)";

This will return me all campaign_ids from table1.

Here is my trouble:

If I want to add in my WHERE, a clause about the month/year, I always get back 0 results.

ie.

"SELECT t1.campaign_id, t2.revenue FROM table1 t1 LEFT JOIN table2 t2 ON t1.campaign_id=t2.campaign_id WHERE (t2.campaign_id IS NULL OR t2.campaign_id IS NOT NULL) AND t2.year=2004 AND t2.month=12";

* Is it possible for me to do this in one query? The results I want are simple, I want each campaign_id in table1 returned, with the revenue they earned IN THAT date range (if any).

Thx in advance !!