SQL> set serveroutput on
SQL> set echo on
SQL>
SQL>
SQL> create table t
2 ( x, y null, primary key (x) )
3 as
4 select rownum x, username
5 from all_users
6 where rownum <= 100;
Table created.
SQL>
SQL> analyze table t compute statistics;
Table analyzed.
SQL>
SQL>
SQL> analyze table t compute statistics for all indexes;
Table analyzed.
SQL>
SQL>
SQL> set autotrace on explain
SQL>
SQL> select count(y) from t where x < 50;
COUNT(Y)
----------
14
1 row selected.
Execution Plan
--------------------------------------------------
Plan hash value: 2966233522
--------------------------------------------------
-------------------------
| Id | Operation | Name | Rows | Bytes
| Cost (%CPU)| Time |
--------------------------------------------------
-------------------------
| 0 | SELECT STATEMENT | | 1 | 8
| 2 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | 8
| | |
|* 2 | TABLE ACCESS FULL| T | 14 | 112
| 2 (0)| 00:00:01 |
--------------------------------------------------
-------------------------
Predicate Information (identified by operation id)
:
--------------------------------------------------
-
2 - filter("X"<50)
SQL>
SQL> drop table t;
Table dropped.
SQL>
SQL> set autotrace off
SQL> --