Outer join with a WHERE clause

Question

hi, this is driving me round the bend. I thought i was ok with sql joins and the like, but im really struggling on this one.
I have table A (for argument sake tblRegion) and table B (tblBranch). if i want to return everything i would do something like this:-
select * from tblRegion join tblBranch on tblRegion.id=tblBranch.reg_id.
If i wanted to return all regions even if they do have a branch associated i would do something like this:-
select * from tblRegion left outer join tblBranch on tblRegion.id=tblBranch.reg_id.
My problem is, I want to return all Regions and use a WHERE clause to narrow the Branch results.
I've tried something like this but it doesnt work
select * from tblRegion left outer join tblBranch on tblRegion.id=tblBranch.reg_id WHERE branch.name like 'LONDON%'
Is there anyway i can return all branches where name is like LONDON, and STILL return all Region if there is no data for that Region?
Do i need to use a nested select statement maybe?
Many thanks in anticipation somebody will save me from my current madness. David

Answer 1

Check this link. It explains the most common problem/coding error while using outer join.
http://www.orafaq.com/node/855
Effectively in your case you need the following condition in your where clause
where nvl(branch.name,'LONDON') like 'LONDON%'
Hope that helps.
Regards
Raj