Oracle: How to Find the Table Size

There are different ways to find table size in oracle, views associated to check size of tables are:

• DBA_EXTENTS
• USER_EXTENTS
• DBA_SEGMENTS

Method 1:

To find size of tables using view DBA_SEGMENTS:

SQL> SELECT SEGMENT_NAME, SEGMENT_TYPE, BYTES/1024/1024 MB, TABLESPACE_NAME

  2  FROM DBA_SEGMENTS

  3  WHERE SEGMENT_TYPE='TABLE' AND SEGMENT_NAME='CUSTOMERS';

SEGMENT_NAME    SEGMENT_TY         MB TABLESPACE_NAME

--------------- ---------- ---------- ------------------------------

CUSTOMERS       TABLE           .0625 SYSTEM

Method 2:

To find size of tables using view DBA_EXTENTS:

SQL>  SELECT SEGMENT_NAME, SEGMENT_TYPE, BYTES/1024/1024 MB, TABLESPACE_NAME

  2   FROM DBA_EXTENTS

  3   WHERE SEGMENT_TYPE='TABLE' AND SEGMENT_NAME='CUSTOMERS';

SEGMENT_NAME    SEGMENT_TY         MB TABLESPACE_NAME

--------------- ---------- ---------- -------------------

CUSTOMERS       TABLE           .0625 SYSTEM

As a user you can also use user_extents.