select fs.tablespace_name, df.file_name, df.blocks, df.blocks-(fs.block_id+fs.blocks), fs.blocks*8192/1024/1024 mb
from dba_free_space fs, dba_data_files df
where fs.file_id = df.file_id
and fs.tablespace_name like 'Q%'
order by 4,5 desc