create table Building (
	id        integer primary key,
	name      varchar(10) not null,
	longname  varchar(40) not null,
	gridref   char(3) -- Grid ref is one letter, followed by up to 2 digits, for example (A1, B11, C20, D9) etc
);

Need to write a query that returns the longname of the building with the highest numeric part of the grid ref. I've written it to use a subquery, but was wondering if there's any way to do it in a single query.

My current query is:

select building.longname FROM building WHERE CAST(substr(building.gridref, 2, 2) as integer) = (SELECT MAX(CAST(substr(building.gridref, 2, 2) as integer)) FROM building)