Query table size including partitions, indexes

Table_Size.sql

SELECT owner,
         table_name,
         TRUNC(sum(bytes)/1024/1024) Meg
FROM 
    (SELECT segment_name table_name,
         owner,
         bytes
    FROM dba_segments
    WHERE segment_type = 'TABLE'
    UNION
    all
    SELECT segment_name table_name,
         owner,
         bytes
    FROM dba_segments
    WHERE segment_type = 'TABLE PARTITION'
    UNION
    ALL
    SELECT i.table_name,
         i.owner,
         s.bytes
    FROM dba_indexes i, dba_segments s
    WHERE s.segment_name = i.index_name
            AND s.owner = i.owner
            AND s.segment_type = 'INDEX'
    UNION
    ALL 
    SELECT l.table_name,
         l.owner,
         s.bytes
    FROM dba_lobs l, dba_segments s
    WHERE s.segment_name = l.segment_name
            AND s.owner = l.owner
            AND s.segment_type = 'LOBSEGMENT'
    UNION
    ALL 
    SELECT l.table_name,
         l.owner,
         s.bytes
    FROM dba_lobs l, dba_segments s
    WHERE s.segment_name = l.index_name
            AND s.owner = l.owner
            AND s.segment_type = 'LOBINDEX')
WHERE 
owner NOT IN ('SYS','OUTLN','SYSTEM','DBSNMP','APPQOSSYS','WMSYS','EXFSYS','CTXSYS','XDB','ORDSYS','ORDDATA','MDSYS' ,'OLAPSYS','SYSMAN','APEX_030200','FLOWS_FILES','SCOTT','OWBSYS')
GROUP BY  table_name, owner
HAVING SUM(bytes)/1024/1024 > 800 /* Ignore really small tables */
ORDER BY  SUM(bytes) desc;