Oracle Sample Statement Learning (ii) Introduction to SEED statements

For ordinary sample statements, the results that Oracle returns each time are not fixed:

Sql> SELECT object_id from T SAMPLE (0.01);

object_id

----------

35199

Execution plan

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

Plan Hash value:2767392432

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

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

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

| 0 |      SELECT STATEMENT |     |    5 |   85 | 157 (2) | 00:00:02 |

|  1 | TABLE ACCESS sample|     T |    5 |   85 | 157 (2) | 00:00:02 |

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

Statistical information

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

1 Recursive calls

0 db Block gets

Consistent gets

0 physical Reads

0 Redo Size

411 Bytes sent via sql*net to client

385 bytes received via sql*net from client

2 sql*net roundtrips To/from Client

0 Sorts (memory)

0 Sorts (disk)

1 rows processed

Sql> SELECT object_id from T SAMPLE (0.01);

object_id

----------

2013

5637

16087

18032

21327

27788

38549

40479

44344

49347

10 rows have been selected.

Execution plan

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

Plan Hash value:2767392432

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

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

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

| 0 |      SELECT STATEMENT |     |    5 |   85 | 157 (2) | 00:00:02 |

|  1 | TABLE ACCESS sample|     T |    5 |   85 | 157 (2) | 00:00:02 |

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

Statistical information

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

0 Recursive calls

0 db Block gets

Consistent gets

0 physical Reads

0 Redo Size

530 Bytes sent via sql*net to client

385 bytes received via sql*net from client

2 sql*net roundtrips To/from Client

0 Sorts (memory)

0 Sorts (disk)

Ten rows processed

Sql> SELECT object_id from T SAMPLE (0.01);

object_id

----------

21949

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