MySQL ORDER BY question, involving two columns!

[gazchap]

I've got a list of suppliers that I want to order by region.

However, the supplier address is made up of 2 fields, "address1" and "address2".

It is possible for end-users to fill in only "address1", or both fields.

If they only enter "address1", the contents of that field is displayed in bold on the page, i.e.:

Staffordshire

If they enter both fields, only address2 is bold:

Cannock, Staffordshire

The list needs to be sorted by the bold bit, and this is where my problem appears.

I need to order the bold bits in alphabetical order, but because they are spread over two columns this doesn't seem easy.

Is there a way of doing it in just one SQL query or am I going to have to do extra processing in PHP?

[Sxooter]

You can probably use coalesce or something like it to make a dummy field to sort by.

select coalesce(field2, field1) as sortby, morefieldshere from table order by sortby