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SQL> CREATE TABLE DETAIL_TABLE                                     
  2  AS SELECT OWNER,OBJECT_NAME from sys.dba_objects; 
Table created.
SQL> DESC DETAIL_TABLE
 Name                               Null?    Type 
 ---------------------------------- -------- --------------
 OWNER                                       VARCHAR2(30)
 OBJECT_NAME                                 VARCHAR2(128)
SQL> CREATE MATERIALIZED VIEW MID_TABLE ENABLE QUERY REWRITE
  2  AS
  3  SELECT OWNER,COUNT(*) TABCNT from DETAIL_TABLE GROUP BY OWNER;
Materialized view created.
SQL> DESC MID_TABLE
 Name