Oracle Database Discussions

col TABLESPACE_NAME format a15;
col MAXSPACE format 9999999;
col USEDSPACE format 999999;
col FREESPACE format 999999;
col "% Free Space" format a6;
select tablespace_name,
sum((((8192*maxextend)/1024)/1024)) maxspace,
((sum(bytes)/1024)/1024) usedspace,
(sum((((8192*maxextend)/1024)/1024)) - ((sum(bytes)/1024)/1024)) freespace,
round((((sum((((8192*maxextend)/1024)/1024)) - ((sum(bytes)/1024)/1024))*100)/sum((((8192*maxextend)/1024)/1024))))||
' %' "% Free Space"
from dba_data_files a,
sys.filext$ b
where a.file_id = b.file#(+)
group by tablespace_name;


AND




SELECT size_free_gb.tablespace_name,
SUM( size_free_gb.size_gb) SIZe_gb,
SUM( size_free_gb.free_gb) free_gb
FROM ( SELECT DFS.FREE_GB,
SUM(DDF.BYTES / 1024 / 1024 / 1024) SIZE_GB,
DDF.FILE_ID,
DDF.TABLESPACE_NAME
FROM (SELECT SUM(BYTES / 1024 / 1024 / 1024) FREE_GB, FILE_ID
FROM DBA_FREE_SPACE
GROUP BY FILE_ID) DFS,DBA_DATA_FILES DDF
WHERE DDF.FILE_ID = DFS.FILE_ID
GROUP BY DDF.FILE_ID, DDF.TABLESPACE_NAME, DFS.FREE_GB) size_free_gb
GROUP BY size_free_gb.tablespace_name;



Why maxextend in first query.... ?

Thanks in Advance..