Which query is efficient?

Hi all,
I have 2 queries which produce same output on test data. But i am not confident which is a better one or efficient one.
How can I measure the efficiency of these programs?
Query1:
SELECT TAB1.A, TAB1.B
FROM TAB1
LEFT OUTER JOIN (SELECT * FROM TAB2 WHERE d=-1) t2
ON TAB1.a = T2.c;
Query2:
SELECT TAB1.A, TAB1.B, TAB2.e
FROM TAB1
LEFT OUTER JOIN TAB2 ON TAB1.a = TAB2.c AND TAB2.d=-1;
Thanks
Edited by: KinsaKaUy? on 10-Oct-2011 02:00

But there should be at least a difference?
I am worried if I cut n paste the same program?
ok I will try again. brb
| Id | Operation                         | Name         | Rows | Bytes | Cost |
|   0 | SELECT STATEMENT                  |              |    15 | 2640 |     6 |
|   1 | NESTED LOOPS                     |              |       |       |       |
|   2 |   NESTED LOOPS                    |              |    15 | 2640 |     6 |
|   3 |    NESTED LOOPS OUTER             |              |     6 |   942 |     5 |
|   4 |     NESTED LOOPS OUTER            |              |     6 |   822 |     4 |
|   5 |      NESTED LOOPS                 |              |     6 |   654 |     3 |
|   6 |       NESTED LOOPS                |              |     6 |   444 |     2 |
|   7 |        TABLE ACCESS BY INDEX ROWID| CI_CASE_CHAR |     7 |   259 |     1 |
|   8 |         INDEX SKIP SCAN           | XT222P0      |     7 |       |     1 |
|   9 |        TABLE ACCESS BY INDEX ROWID| CI_CASE_CHAR |     1 |    37 |     1 |
| 10 |         INDEX RANGE SCAN          | XT222P0      |     1 |       |     1 |
| 11 |       TABLE ACCESS BY INDEX ROWID | CI_CASE      |     1 |    35 |     1 |
| 12 |        INDEX UNIQUE SCAN          | XT220P0      |     1 |       |     1 |
| 13 |      TABLE ACCESS BY INDEX ROWID | CI_CASE_CHAR |     1 |    28 |     1 |
| 14 |       INDEX RANGE SCAN            | XT222P0      |     1 |       |     1 |
| 15 |     TABLE ACCESS BY INDEX ROWID   | CI_SP        |     1 |    20 |     1 |
| 16 |      INDEX UNIQUE SCAN            | XM226P0      |     1 |       |     1 |
| 17 |    INDEX RANGE SCAN               | XT221P0      |     3 |       |     1 |
| 18 |   TABLE ACCESS BY INDEX ROWID     | CI_CASE_LOG |     3 |    57 |     1 |
| Id | Operation                         | Name         | Rows | Bytes | Cost |
|   0 | SELECT STATEMENT                  |              |    15 | 2640 |     6 |
|   1 | NESTED LOOPS                     |              |       |       |       |
|   2 |   NESTED LOOPS                    |              |    15 | 2640 |     6 |
|   3 |    NESTED LOOPS OUTER             |              |     6 |   942 |     5 |
|   4 |     NESTED LOOPS OUTER            |              |     6 |   822 |     4 |
|   5 |      NESTED LOOPS                 |              |     6 |   654 |     3 |
|   6 |       NESTED LOOPS                |              |     6 |   444 |     2 |
|   7 |        TABLE ACCESS BY INDEX ROWID| CI_CASE_CHAR |     7 |   259 |     1 |
|   8 |         INDEX SKIP SCAN           | XT222P0      |     7 |       |     1 |
|   9 |        TABLE ACCESS BY INDEX ROWID| CI_CASE_CHAR |     1 |    37 |     1 |
| 10 |         INDEX RANGE SCAN          | XT222P0      |     1 |       |     1 |
| 11 |       TABLE ACCESS BY INDEX ROWID | CI_CASE      |     1 |    35 |     1 |
| 12 |        INDEX UNIQUE SCAN          | XT220P0      |     1 |       |     1 |
| 13 |      TABLE ACCESS BY INDEX ROWID | CI_CASE_CHAR |     1 |    28 |     1 |
| 14 |       INDEX RANGE SCAN            | XT222P0      |     1 |       |     1 |
| 15 |     TABLE ACCESS BY INDEX ROWID   | CI_SP        |     1 |    20 |     1 |
| 16 |      INDEX UNIQUE SCAN            | XM226P0      |     1 |       |     1 |
| 17 |    INDEX RANGE SCAN               | XT221P0      |     3 |       |     1 |
| 18 |   TABLE ACCESS BY INDEX ROWID     | CI_CASE_LOG |     3 |    57 |     1 |
I guess they are identical :)
Edited by: KinsaKaUy? on Oct 10, 2011 2:40 AM

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