需要關於優化SQL select語句的幫助

我是Oracle數據庫的新手。 'select'語句會導致性能問題。問題是，象下面這樣：需要關於優化SQL select語句的幫助

聲明原件（工作非常慢）：

SELECT * 
FROM my_pos pos 
WHERE my_source NOT IN 
    (SELECT my_source_id FROM my_source WHERE can_delete = 0 
) 
AND EXISTS 
    (SELECT 1 
    FROM my_agreement agr, 
    my_account acc, 
    my_account fund_acc, 
    my_client cli, 
    WHERE (agr.agr_client_acc_id = pos.my_acc_id 
    OR agr.agr_cp_acc_id   = pos.my_acc_id 
    OR agr.agr_client_coll_acc_id = pos.my_acc_id 
    OR agr.agr_pool_acc_id  = pos.my_acc_id 
    OR agr.client_pool_acc_id  = pos.my_acc_id) 
    AND agr.agr_client_acc_id  = acc.my_acc_id 
    AND acc.fund_acc_id   = fund_acc.my_acc_id(+) 
    AND cli.client_id    = (
    CASE 
     WHEN fund_acc.my_acc_id IS NOT NULL 
     THEN fund_acc.client_id 
     ELSE acc.client_id 
    END) 
);

解釋計劃爲聲明原文：

Plan hash value: 4147965473 

-------------------------------------------------------------------------------------------- 
| Id | Operation     | Name   | Rows | Bytes | Cost (%CPU)| Time  | 
-------------------------------------------------------------------------------------------- 
| 0 | SELECT STATEMENT   |    | 1748 | 290K| 2532 (4)| 00:00:31 | 
|* 1 | HASH JOIN SEMI   |    | 1748 | 290K| 2532 (4)| 00:00:31 | 
|* 2 | HASH JOIN RIGHT ANTI  |    | 1748 | 268K| 1364 (2)| 00:00:17 | 
|* 3 | TABLE ACCESS FULL  | MY_SOURCE  | 44 | 264 |  2 (0)| 00:00:01 | 
| 4 | TABLE ACCESS FULL  | MY_POS  | 8738 | 1288K| 1361 (2)| 00:00:17 | 
| 5 | VIEW      | VW_SQ_1  | 16285 | 206K| 1167 (6)| 00:00:15 | 
| 6 | UNION-ALL    |    |  |  |   |   | 
| 7 |  NESTED LOOPS   |    | 3257 | 78168 | 211 (7)| 00:00:03 | 
|* 8 |  HASH JOIN OUTER  |    | 3257 | 68397 | 209 (6)| 00:00:03 | 
|* 9 |  HASH JOIN   |    | 3257 | 45598 | 107 (6)| 00:00:02 | 
| 10 |  INDEX FAST FULL SCAN| IX_AGR_CLIENT | 3257 | 13028 |  4 (0)| 00:00:01 | 
| 11 |  TABLE ACCESS FULL | MY_ACCOUNT || 226K| 101 (4)| 00:00:02 | 
| 12 |  TABLE ACCESS FULL | MY_ACCOUNT || 158K| 100 (3)| 00:00:02 | 
|* 13 |  INDEX UNIQUE SCAN  | PK_CLIENT  |  1 |  3 |  0 (0)| 00:00:01 | 
| 14 |  NESTED LOOPS   |    | 3257 | 91196 | 238 (6)| 00:00:03 | 
|* 15 |  HASH JOIN OUTER  |    | 3257 | 81425 | 236 (5)| 00:00:03 | 
|* 16 |  HASH JOIN   |    | 3257 | 58626 | 135 (6)| 00:00:02 | 
| 17 |  TABLE ACCESS FULL | MY_AGREEMENT | 3257 | 26056 | 32 (4)| 00:00:01 | 
| 18 |  TABLE ACCESS FULL | MY_ACCOUNT || 226K| 101 (4)| 00:00:02 | 
| 19 |  TABLE ACCESS FULL | MY_ACCOUNT || 158K| 100 (3)| 00:00:02 | 
|* 20 |  INDEX UNIQUE SCAN  | PK_CLIENT  |  1 |  3 |  0 (0)| 00:00:01 | 
| 21 |  NESTED LOOPS   |    | 3257 | 84682 | 239 (6)| 00:00:03 | 
|* 22 |  HASH JOIN OUTER  |    | 3257 | 74911 | 236 (5)| 00:00:03 | 
|* 23 |  HASH JOIN   |    | 3257 | 52112 | 135 (6)| 00:00:02 | 
| 24 |  TABLE ACCESS FULL | MY_AGREEMENT | 3257 | 19542 | 32 (4)| 00:00:01 | 
| 25 |  TABLE ACCESS FULL | MY_ACCOUNT || 226K| 101 (4)| 00:00:02 | 
| 26 |  TABLE ACCESS FULL | MY_ACCOUNT || 158K| 100 (3)| 00:00:02 | 
|* 27 |  INDEX UNIQUE SCAN  | PK_CLIENT  |  1 |  3 |  0 (0)| 00:00:01 | 
| 28 |  NESTED LOOPS   |    | 3257 | 84682 | 239 (6)| 00:00:03 | 
|* 29 |  HASH JOIN OUTER  |    | 3257 | 74911 | 236 (5)| 00:00:03 | 
|* 30 |  HASH JOIN   |    | 3257 | 52112 | 135 (6)| 00:00:02 | 
| 31 |  TABLE ACCESS FULL | MY_AGREEMENT | 3257 | 19542 | 32 (4)| 00:00:01 | 
| 32 |  TABLE ACCESS FULL | MY_ACCOUNT || 226K| 101 (4)| 00:00:02 | 
| 33 |  TABLE ACCESS FULL | MY_ACCOUNT || 158K| 100 (3)| 00:00:02 | 
|* 34 |  INDEX UNIQUE SCAN  | PK_CLIENT  |  1 |  3 |  0 (0)| 00:00:01 | 
| 35 |  NESTED LOOPS   |    | 3257 | 84682 | 240 (7)| 00:00:03 | 
|* 36 |  HASH JOIN OUTER  |    | 3257 | 74911 | 237 (6)| 00:00:03 | 
|* 37 |  HASH JOIN   |    | 3257 | 52112 | 136 (6)| 00:00:02 | 
| 38 |  TABLE ACCESS FULL | MY_AGREEMENT | 3257 | 19542 | 33 (7)| 00:00:01 | 
| 39 |  TABLE ACCESS FULL | MY_ACCOUNT || 226K| 101 (4)| 00:00:02 | 
| 40 |  TABLE ACCESS FULL | MY_ACCOUNT || 158K| 100 (3)| 00:00:02 | 
|* 41 |  INDEX UNIQUE SCAN  | PK_CLIENT  |  1 |  3 |  0 (0)| 00:00:01 | 
-------------------------------------------------------------------------------------------- 

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

    1 - access("VW_COL_1"="POS"."MY_ACC_ID") 
    2 - access("MY_SOURCE"="MY_SOURCE_ID") 
    3 - filter("CAN_DELETE"=0) 
    8 - access("ACC"."FUND_ACC_ID"="FUND_ACC"."MY_ACC_ID"(+)) 
    9 - access("AGR"."AGR_CLIENT_ACC_ID"="ACC"."MY_ACC_ID") 
    13 - access("CLI"."CLIENT_ID"=CASE WHEN ("FUND_ACC"."MY_ACC_ID" IS NOT NULL) 
       THEN "FUND_ACC"."CLIENT_ID" ELSE "ACC"."CLIENT_ID" END) 
    15 - access("ACC"."FUND_ACC_ID"="FUND_ACC"."MY_ACC_ID"(+)) 
    16 - access("AGR"."AGR_CLIENT_ACC_ID"="ACC"."MY_ACC_ID") 
    20 - access("CLI"."CLIENT_ID"=CASE WHEN ("FUND_ACC"."MY_ACC_ID" IS NOT NULL) 
       THEN "FUND_ACC"."CLIENT_ID" ELSE "ACC"."CLIENT_ID" END) 
    22 - access("ACC"."FUND_ACC_ID"="FUND_ACC"."MY_ACC_ID"(+)) 
    23 - access("AGR"."AGR_CLIENT_ACC_ID"="ACC"."MY_ACC_ID") 
    27 - access("CLI"."CLIENT_ID"=CASE WHEN ("FUND_ACC"."MY_ACC_ID" IS NOT NULL) 
       THEN "FUND_ACC"."CLIENT_ID" ELSE "ACC"."CLIENT_ID" END) 
    29 - access("ACC"."FUND_ACC_ID"="FUND_ACC"."MY_ACC_ID"(+)) 
    30 - access("AGR"."AGR_CLIENT_ACC_ID"="ACC"."MY_ACC_ID") 
    34 - access("CLI"."CLIENT_ID"=CASE WHEN ("FUND_ACC"."MY_ACC_ID" IS NOT NULL) 
       THEN "FUND_ACC"."CLIENT_ID" ELSE "ACC"."CLIENT_ID" END) 
    36 - access("ACC"."FUND_ACC_ID"="FUND_ACC"."MY_ACC_ID"(+)) 
    37 - access("AGR"."AGR_CLIENT_ACC_ID"="ACC"."MY_ACC_ID") 
    41 - access("CLI"."CLIENT_ID"=CASE WHEN ("FUND_ACC"."MY_ACC_ID" IS NOT NULL) 
       THEN "FUND_ACC"."CLIENT_ID" ELSE "ACC"."CLIENT_ID" END)

新聲明（作品非常快）：

SELECT * 
FROM my_pos pos1 
WHERE my_source NOT IN 
    (SELECT my_source_id FROM my_source WHERE can_delete = 0 
) 
AND EXISTS 
    (SELECT 1 
    FROM my_agreement agr, 
    my_account acc, 
    my_account fund_acc, 
    my_client cli, 
    -- add my_pos here 
    my_pos pos 
    WHERE (agr.agr_client_acc_id = pos.my_acc_id 
    OR agr.agr_cp_acc_id   = pos.my_acc_id 
    OR agr.agr_client_coll_acc_id = pos.my_acc_id 
    OR agr.agr_pool_acc_id  = pos.my_acc_id 
    OR agr.client_pool_acc_id  = pos.my_acc_id) 
    AND agr.agr_client_acc_id  = acc.my_acc_id 
    AND acc.fund_acc_id   = fund_acc.my_acc_id(+) 
    AND cli.client_id    = (
    CASE 
     WHEN fund_acc.my_acc_id IS NOT NULL 
     THEN fund_acc.client_id 
     ELSE acc.client_id 
    END) 
    -- connect pos1 and pos 
    AND pos1.my_pos_id = pos.my_pos_id 
);

新語句解釋計劃：

Plan hash value: 2962711282 

---------------------------------------------------------------------------------------------------- 
| Id | Operation       | Name   | Rows | Bytes | Cost (%CPU)| Time  | 
---------------------------------------------------------------------------------------------------- 
| 0 | SELECT STATEMENT     |    | 1748 | 290K| 9174 (2)| 00:01:51 | 
|* 1 | HASH JOIN SEMI     |    | 1748 | 290K| 9174 (2)| 00:01:51 | 
|* 2 | HASH JOIN RIGHT ANTI    |    | 1748 | 268K| 1364 (2)| 00:00:17 | 
|* 3 | TABLE ACCESS FULL    | MY_SOURCE  | 44 | 264 |  2 (0)| 00:00:01 | 
| 4 | TABLE ACCESS FULL    | MY_POS  | 8738 | 1288K| 1361 (2)| 00:00:17 | 
| 5 | VIEW        | VW_SQ_1  | 32799 | 416K| 7809 (2)| 00:01:34 | 
| 6 | CONCATENATION     |    |  |  |   |   | 
|* 7 |  HASH JOIN      |    | 1277 | 54911 | 1439 (2)| 00:00:18 | 
| 8 |  NESTED LOOPS     |    | 25 | 850 | 83 (3)| 00:00:01 | 
| 9 |  NESTED LOOPS OUTER   |    | 25 | 775 | 83 (3)| 00:00:01 | 
| 10 |  NESTED LOOPS    |    | 25 | 600 | 58 (4)| 00:00:01 | 
|* 11 |   TABLE ACCESS FULL   | MY_AGREEMENT | 25 | 350 | 33 (7)| 00:00:01 | 
| 12 |   TABLE ACCESS BY INDEX ROWID| MY_ACCOUNT |  1 | 10 |  1 (0)| 00:00:01 | 
|* 13 |   INDEX UNIQUE SCAN   | PK_MY_ACCOUNT |  1 |  |  0 (0)| 00:00:01 | 
| 14 |  TABLE ACCESS BY INDEX ROWID | MY_ACCOUNT |  1 |  7 |  1 (0)| 00:00:01 | 
|* 15 |   INDEX UNIQUE SCAN   | PK_MY_ACCOUNT |  1 |  |  0 (0)| 00:00:01 | 
|* 16 |  INDEX UNIQUE SCAN   | PK_CLIENT  |  1 |  3 |  0 (0)| 00:00:01 | 
| 17 |  TABLE ACCESS FULL    | MY_POS  | 8738 | 78642 | 1356 (2)| 00:00:17 | 
|* 18 |  HASH JOIN      |    | 4956 | 208K| 1583 (2)| 00:00:19 | 
| 19 |  NESTED LOOPS     |    | 97 | 3298 | 227 (1)| 00:00:03 | 
| 20 |  NESTED LOOPS OUTER   |    | 97 | 3007 | 227 (1)| 00:00:03 | 
| 21 |  NESTED LOOPS    |    | 97 | 2328 | 129 (1)| 00:00:02 | 
|* 22 |   TABLE ACCESS FULL   | MY_AGREEMENT | 97 | 1358 | 32 (4)| 00:00:01 | 
| 23 |   TABLE ACCESS BY INDEX ROWID| MY_ACCOUNT |  1 | 10 |  1 (0)| 00:00:01 | 
|* 24 |   INDEX UNIQUE SCAN   | PK_MY_ACCOUNT |  1 |  |  0 (0)| 00:00:01 | 
| 25 |  TABLE ACCESS BY INDEX ROWID | MY_ACCOUNT |  1 |  7 |  1 (0)| 00:00:01 | 
|* 26 |   INDEX UNIQUE SCAN   | PK_MY_ACCOUNT |  1 |  |  0 (0)| 00:00:01 | 
|* 27 |  INDEX UNIQUE SCAN   | PK_CLIENT  |  1 |  3 |  0 (0)| 00:00:01 | 
| 28 |  TABLE ACCESS FULL    | MY_POS  | 8738 | 78642 | 1356 (2)| 00:00:17 | 
|* 29 |  HASH JOIN      |    | 8736 | 366K| 1594 (2)| 00:00:20 | 
| 30 |  NESTED LOOPS     |    | 776 | 26384 | 237 (6)| 00:00:03 | 
|* 31 |  HASH JOIN OUTER    |    | 776 | 24056 | 236 (5)| 00:00:03 | 
|* 32 |  HASH JOIN     |    | 776 | 18624 | 135 (6)| 00:00:02 | 
|* 33 |   TABLE ACCESS FULL   | MY_AGREEMENT | 776 | 10864 | 32 (4)| 00:00:01 | 
| 34 |   TABLE ACCESS FULL   | MY_ACCOUNT || 226K| 101 (4)| 00:00:02 | 
| 35 |  TABLE ACCESS FULL   | MY_ACCOUNT || 158K| 100 (3)| 00:00:02 | 
|* 36 |  INDEX UNIQUE SCAN   | PK_CLIENT  |  1 |  3 |  0 (0)| 00:00:01 | 
| 37 |  TABLE ACCESS FULL    | MY_POS  | 8738 | 78642 | 1356 (2)| 00:00:17 | 
|* 38 |  HASH JOIN      |    | 8733 | 366K| 1596 (2)| 00:00:20 | 
| 39 |  NESTED LOOPS     |    | 3075 | 102K| 239 (6)| 00:00:03 | 
|* 40 |  HASH JOIN OUTER    |    | 3075 | 95325 | 237 (6)| 00:00:03 | 
|* 41 |  HASH JOIN     |    | 3075 | 73800 | 136 (6)| 00:00:02 | 
|* 42 |   TABLE ACCESS FULL   | MY_AGREEMENT | 3075 | 43050 | 33 (7)| 00:00:01 | 
| 43 |   TABLE ACCESS FULL   | MY_ACCOUNT || 226K| 101 (4)| 00:00:02 | 
| 44 |  TABLE ACCESS FULL   | MY_ACCOUNT || 158K| 100 (3)| 00:00:02 | 
|* 45 |  INDEX UNIQUE SCAN   | PK_CLIENT  |  1 |  3 |  0 (0)| 00:00:01 | 
| 46 |  TABLE ACCESS FULL    | MY_POS  | 8738 | 78642 | 1356 (2)| 00:00:17 | 
|* 47 |  HASH JOIN      |    | 9097 | 382K| 1596 (2)| 00:00:20 | 
| 48 |  NESTED LOOPS     |    | 3257 | 108K| 240 (7)| 00:00:03 | 
|* 49 |  HASH JOIN OUTER    |    | 3257 | 98K| 237 (6)| 00:00:03 | 
|* 50 |  HASH JOIN     |    | 3257 | 78168 | 136 (6)| 00:00:02 | 
| 51 |   TABLE ACCESS FULL   | MY_AGREEMENT | 3257 | 45598 | 33 (7)| 00:00:01 | 
| 52 |   TABLE ACCESS FULL   | MY_ACCOUNT || 226K| 101 (4)| 00:00:02 | 
| 53 |  TABLE ACCESS FULL   | MY_ACCOUNT || 158K| 100 (3)| 00:00:02 | 
|* 54 |  INDEX UNIQUE SCAN   | PK_CLIENT  |  1 |  3 |  0 (0)| 00:00:01 | 
| 55 |  TABLE ACCESS FULL    | MY_POS  | 8738 | 78642 | 1356 (2)| 00:00:17 | 
---------------------------------------------------------------------------------------------------- 

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

    1 - access("POS1"."MY_POS_ID"="ITEM_1") 
    2 - access("MY_SOURCE"="MY_SOURCE_ID") 
    3 - filter("CAN_DELETE"=0) 
    7 - access("AGR"."CLIENT_POOL_ACC_ID"="POS"."MY_ACC_ID") 
    11 - filter("AGR"."CLIENT_POOL_ACC_ID" IS NOT NULL) 
    13 - access("AGR"."AGR_CLIENT_ACC_ID"="ACC"."MY_ACC_ID") 
    15 - access("ACC"."FUND_ACC_ID"="FUND_ACC"."MY_ACC_ID"(+)) 
    16 - access("CLI"."CLIENT_ID"=CASE WHEN ("FUND_ACC"."MY_ACC_ID" IS NOT NULL) THEN 
       "FUND_ACC"."CLIENT_ID" ELSE "ACC"."CLIENT_ID" END) 
    18 - access("AGR"."AGR_POOL_ACC_ID"="POS"."MY_ACC_ID") 
     filter(LNNVL("AGR"."CLIENT_POOL_ACC_ID"="POS"."MY_ACC_ID") OR 
       LNNVL("AGR"."CLIENT_POOL_ACC_ID" IS NOT NULL)) 
    22 - filter("AGR"."AGR_POOL_ACC_ID" IS NOT NULL) 
    24 - access("AGR"."AGR_CLIENT_ACC_ID"="ACC"."MY_ACC_ID") 
    26 - access("ACC"."FUND_ACC_ID"="FUND_ACC"."MY_ACC_ID"(+)) 
    27 - access("CLI"."CLIENT_ID"=CASE WHEN ("FUND_ACC"."MY_ACC_ID" IS NOT NULL) THEN 
       "FUND_ACC"."CLIENT_ID" ELSE "ACC"."CLIENT_ID" END) 
    29 - access("AGR"."AGR_CLIENT_COLL_ACC_ID"="POS"."MY_ACC_ID") 
     filter((LNNVL("AGR"."AGR_POOL_ACC_ID"="POS"."MY_ACC_ID") OR 
       LNNVL("AGR"."AGR_POOL_ACC_ID" IS NOT NULL)) AND 
       (LNNVL("AGR"."CLIENT_POOL_ACC_ID"="POS"."MY_ACC_ID") OR LNNVL("AGR"."CLIENT_POOL_ACC_ID" IS 
       NOT NULL))) 
    31 - access("ACC"."FUND_ACC_ID"="FUND_ACC"."MY_ACC_ID"(+)) 
    32 - access("AGR"."AGR_CLIENT_ACC_ID"="ACC"."MY_ACC_ID") 
    33 - filter("AGR"."AGR_CLIENT_COLL_ACC_ID" IS NOT NULL) 
    36 - access("CLI"."CLIENT_ID"=CASE WHEN ("FUND_ACC"."MY_ACC_ID" IS NOT NULL) THEN 
       "FUND_ACC"."CLIENT_ID" ELSE "ACC"."CLIENT_ID" END) 
    38 - access("AGR"."AGR_CP_ACC_ID"="POS"."MY_ACC_ID") 
     filter((LNNVL("AGR"."AGR_CLIENT_COLL_ACC_ID"="POS"."MY_ACC_ID") OR 
       LNNVL("AGR"."AGR_CLIENT_COLL_ACC_ID" IS NOT NULL)) AND 
       (LNNVL("AGR"."AGR_POOL_ACC_ID"="POS"."MY_ACC_ID") OR LNNVL("AGR"."AGR_POOL_ACC_ID" IS NOT 
       NULL)) AND (LNNVL("AGR"."CLIENT_POOL_ACC_ID"="POS"."MY_ACC_ID") OR 
       LNNVL("AGR"."CLIENT_POOL_ACC_ID" IS NOT NULL))) 
    40 - access("ACC"."FUND_ACC_ID"="FUND_ACC"."MY_ACC_ID"(+)) 
    41 - access("AGR"."AGR_CLIENT_ACC_ID"="ACC"."MY_ACC_ID") 
    42 - filter("AGR"."AGR_CP_ACC_ID" IS NOT NULL) 
    45 - access("CLI"."CLIENT_ID"=CASE WHEN ("FUND_ACC"."MY_ACC_ID" IS NOT NULL) THEN 
       "FUND_ACC"."CLIENT_ID" ELSE "ACC"."CLIENT_ID" END) 
    47 - access("AGR"."AGR_CLIENT_ACC_ID"="POS"."MY_ACC_ID") 
     filter((LNNVL("AGR"."AGR_CP_ACC_ID"="POS"."MY_ACC_ID") OR 
       LNNVL("AGR"."AGR_CP_ACC_ID" IS NOT NULL)) AND 
       (LNNVL("AGR"."AGR_CLIENT_COLL_ACC_ID"="POS"."MY_ACC_ID") OR 
       LNNVL("AGR"."AGR_CLIENT_COLL_ACC_ID" IS NOT NULL)) AND 
       (LNNVL("AGR"."AGR_POOL_ACC_ID"="POS"."MY_ACC_ID") OR LNNVL("AGR"."AGR_POOL_ACC_ID" IS NOT 
       NULL)) AND (LNNVL("AGR"."CLIENT_POOL_ACC_ID"="POS"."MY_ACC_ID") OR 
       LNNVL("AGR"."CLIENT_POOL_ACC_ID" IS NOT NULL))) 
    49 - access("ACC"."FUND_ACC_ID"="FUND_ACC"."MY_ACC_ID"(+)) 
    50 - access("AGR"."AGR_CLIENT_ACC_ID"="ACC"."MY_ACC_ID") 
    54 - access("CLI"."CLIENT_ID"=CASE WHEN ("FUND_ACC"."MY_ACC_ID" IS NOT NULL) THEN 
       "FUND_ACC"."CLIENT_ID" ELSE "ACC"."CLIENT_ID" END)

我的新選擇語句的工作速度比舊的快得多（快80倍！），但我不知道爲什麼。

我只是將目標表添加到子語句中（新的插入語句跟隨我的註釋），並且幾次運行這兩個語句。他們兩人都給了我相同的結果。然而，原來的平均花費80秒，而新的平均花費1秒。有沒有人可以告訴我爲什麼是這種情況？大部分細節是受歡迎的

最好的方面。

來源

2015-06-29 diabolicss

在2015年人們還在使用非ANSI風格的外連接..聳聳肩。 – ErikE

我會先看看你的陳述的execution plans。

1）創建一個執行計劃：

explain plan for (select * from table_name where ...);

2）顯示執行計劃：

select * from table(dbms_xplan.display);

在SQL * Plus你可能也想用只使用AUTO TRACE選項。

這讓您看到Oracle如何執行您的語句，並且是語句級別上任何性能問題的起點。

來源

2015-06-29 05:34:03 doberkofler

感謝您的回答。你能告訴我如何使用AUTO TRACE選項嗎？ – diabolicss

舊的陳述計劃和新的陳述計劃太長了，無法粘貼 – diabolicss

您好，我已將解釋計劃粘貼到我的問題中。請看看他們。最好的祝福。 – diabolicss

我相信，一旦在查詢中添加了'AND pos1.my_pos_id = pos.my_pos_id'這個句子，oracle就可以把查詢當作「內部連接」， - 執行第三個select語句一次，然後使用索引（&外鍵）來決定返回哪些記錄。在第一個查詢，在源表中的每個記錄單獨執行SELECT語句（my_pos）

您的查詢等於：

SELECT * 
FROM my_pos pos1 
    left join 
    my_sourc m on m.my_source_id=pos1.my_source 
    inner join 
    (SELECT my_pos_id 
     FROM my_agreement agr, 
     my_account acc, 
     my_account fund_acc, 
     my_client cli, 
     -- add my_pos here 
     my_pos pos 
     WHERE (agr.agr_client_acc_id = pos.my_acc_id 
     OR agr.agr_cp_acc_id   = pos.my_acc_id 
     OR agr.agr_client_coll_acc_id = pos.my_acc_id 
     OR agr.agr_pool_acc_id  = pos.my_acc_id 
     OR agr.client_pool_acc_id  = pos.my_acc_id) 
     AND agr.agr_client_acc_id  = acc.my_acc_id 
     AND acc.fund_acc_id   = fund_acc.my_acc_id(+) 
     AND cli.client_id    = (
     CASE 
      WHEN fund_acc.my_acc_id IS NOT NULL 
      THEN fund_acc.client_id 
      ELSE acc.client_id 
     END) 


      ) 
     -- connect pos1 and pos 
      on pos1.my_pos_id = pos.my_pos_id 

      where pos1.my_source is null -- this row says, my source not in   my source table there for I accept only nulls

來源

2015-06-29 05:50:22

感謝您的回答。 '你的意思是'在你的第一個查詢中，select語句對源表（my_pos）'中的每個記錄單獨執行？我仍然對這一點感到困惑。 – diabolicss

需要關於優化SQL select語句的幫助

回答

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