测试使用hr用户下的employees和departments表写一条SQL语句，(MG连接)

Posted 2020-08-15 Tomatoes

SQL> select * from employees d, departments t where d.department_id=t.department_id;

106 rows selected.


Execution Plan
----------------------------------------------------------
Plan hash value: 1343509718

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

| Id  | Operation                    | Name        | Rows  | Bytes | Cost (%CPU)
| Time     |

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

|   0 | SELECT STATEMENT             |             |   106 |  9540 |     6  (17)
| 00:00:01 |

|   1 |  MERGE JOIN                  |             |   106 |  9540 |     6  (17)
| 00:00:01 |

|   2 |   TABLE ACCESS BY INDEX ROWID| DEPARTMENTS |    27 |   567 |     2   (0)
| 00:00:01 |

|   3 |    INDEX FULL SCAN           | DEPT_ID_PK  |    27 |       |     1   (0)
| 00:00:01 |

|*  4 |   SORT JOIN                  |             |   107 |  7383 |     4  (25)
| 00:00:01 |

|   5 |    TABLE ACCESS FULL         | EMPLOYEES   |   107 |  7383 |     3   (0)
| 00:00:01 |

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


Predicate Information (identified by operation id):
---------------------------------------------------

   4 - access("D"."DEPARTMENT_ID"="T"."DEPARTMENT_ID")
       filter("D"."DEPARTMENT_ID"="T"."DEPARTMENT_ID")


Statistics
----------------------------------------------------------
          8  recursive calls
          0  db block gets
         20  consistent gets
          0  physical reads