SQL> show user
USER is "SA"
SQL>
SQL> select last_analyzed from dba_tables where table_name='EMP' and owner='SA';
LAST_ANAL
---------
30-DEC-15
SQL> select * from emp;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
1 11
2 80
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30
7566 JONES MANAGER 7839 02-APR-81 2975 20
7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-MAY-81 2850 30
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7788 SCOTT ANALYST 7566 19-APR-87 3000 20
7839 KING PRESIDENT 17-NOV-81 5000 10
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788 23-MAY-87 1100 20
7900 JAMES CLERK 7698 03-DEC-81 950 30
7902 FORD ANALYST 7566 03-DEC-81 3000 20
7934 MILLER CLERK 7782 23-JAN-82 1300 10
16 rows selected.
SQL> select column_name,num_distinct from dba_tab_columns where table_name='EMP' and owner='SA';
COLUMN_NAME NUM_DISTINCT
------------------------------ ------------
EMPNO 14
ENAME 14
JOB 5
MGR 6
HIREDATE 13
SAL 12
COMM 4
DEPTNO 3
8 rows selected.
SQL> exec DBMS_STATS.GATHER_TABLE_STATS(ownname=>'SA',tabname=>'EMP',ESTIMATE_PERCENT=>1,method_opt=>'for all columns size 1',cascade=>true,force=>true,degree=>4);
PL/SQL procedure successfully completed.
SQL> select column_name,num_distinct from dba_tab_columns where table_name='EMP' and owner='SA';
COLUMN_NAME NUM_DISTINCT
------------------------------ ------------
EMPNO 16
ENAME 14
JOB 5
MGR 6
HIREDATE 13
SAL 12
COMM 4
DEPTNO 5
8 rows selected.
SQL>
SQL> select last_analyzed from dba_tables where table_name='EMP' and owner='SA';
LAST_ANAL
---------
03-JAN-16
SQL>
妈呀，怎么时间不对。。。我系统时间错了~~
SQL> !date
Sun Jan 3 19:20:58 CST 2016
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