DECLARE @Temp TABLE( [Name] VARCHAR(1000), db_size VARCHAR(1000), [owner] VARCHAR(1000),
[dbid] VARCHAR(1000), created VARCHAR(1000), [status] VARCHAR(1000),
[compatibility_level] VARCHAR(1000))
INSERT INTO @Temp EXECUTE sp_helpdb
SELECT TOP (5) [Name], db_size AS [Size]
FROM @Temp
ORDER BY CAST( REPLACE( db_size, 'MB', '' ) AS REAL ) DESC