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有沒有人知道爲什麼，我有這3個查詢，最快的是使用where not exists？Oracle查詢調整
這篇文章Rewrite SQL Subqueries as Outer Joins說，你可以將where not exists更改爲正常join。我誤解了嗎？有人可以解釋這種差異嗎？
這一個做它在0.73秒獲取所有3293行
SELECT *
FROM
(SELECT TRIM(TO_CHAR(C21.PINO,'999999999999999')) DN,
C21.INVD,
TRIM(TO_CHAR(C21.ORNO,'999999999999999')),
C21.CFRW,
C21.LIFEX,
C22.PONO,
C22.ITEM,
C22.OQUA,
C71.REFA,
C71.CDEC,
C81.COPO,
DECODE(SUBSTR(TRIM(C22.ITEM),1,3), 'PRD', 1, 'ASY', 2, 'SLA', 3),
C84.NAMA,
C84.CCTY
FROM [email protected]_CMS_PRD C21,
[email protected]_CMS_PRD C22,
[email protected]_CMS_PRD C71,
[email protected]_CMS_PRD C81,
[email protected]_CMS_PRD C84
WHERE C21.PINO = C22.PINO
AND DECODE(SUBSTR(TRIM(C22.ITEM),1,3) , 'PRD', 'Y', 'ASY', 'Y', 'SLA', 'Y', 'N') = 'Y'
AND C21.ORNO = C71.ORNO
AND C21.ORNO = C81.ORNO
AND C22.PONO = C81.PONO
AND C21.ORNO = C84.ORNO
AND C84.CTYP = 'ST'
AND C21.NCMP = 'F555'
AND C21.INVD >= TO_DATE('01012011','MMDDYYYY')
ORDER BY C21.PINO,
C22.PONO
) T1
WHERE NOT EXISTS
(SELECT 1 FROM SHIPPINGCONTROL S WHERE T1.DN=S.S_DN
) ;
這一個做它在2秒內
SELECT TRIM(TO_CHAR(C21.PINO,'999999999999999')) DN,
C21.INVD,
TRIM(TO_CHAR(C21.ORNO,'999999999999999')),
C21.CFRW,
C21.LIFEX,
C22.PONO,
C22.ITEM,
C22.OQUA,
C71.REFA,
C71.CDEC,
C81.COPO,
DECODE(SUBSTR(TRIM(C22.ITEM),1,3),'PRD',1,'ASY',2,'SLA',3),
C84.NAMA,
C84.CCTY
FROM [email protected]_CMS_PRD C21,
[email protected]_CMS_PRD C22,
[email protected]_CMS_PRD C71,
[email protected]_CMS_PRD C81,
[email protected]_CMS_PRD C84,
(SELECT C21.PINO DN
FROM [email protected]_CMS_PRD C21
WHERE C21.INVD>=TO_DATE('01012011','MMDDYYYY')
AND C21.NCMP ='F555'
MINUS
SELECT TO_NUMBER(G_DN) FROM GENERALINFO
) DNSTOFIND
WHERE C21.PINO =C22.PINO
AND DECODE(SUBSTR(TRIM(C22.ITEM),1,3),'PRD','Y','ASY','Y','SLA','Y','N')='Y'
AND C21.ORNO =C71.ORNO
AND C21.ORNO =C81.ORNO
AND C22.PONO =C81.PONO
AND C21.ORNO =C84.ORNO
AND C84.CTYP ='ST'
AND DNSTOFIND.DN =C21.PINO
ORDER BY C21.PINO,
C22.PONO;
這一個做它在4秒
SELECT TRIM(TO_CHAR(C21.PINO,'999999999999999')) DN,
C21.INVD,
TRIM(TO_CHAR(C21.ORNO,'999999999999999')),
C21.CFRW,
C21.LIFEX,
C22.PONO,
C22.ITEM,
C22.OQUA,
C71.REFA,
C71.CDEC,
C81.COPO,
DECODE(SUBSTR(TRIM(C22.ITEM),1,3),'PRD',1,'ASY',2,'SLA',3),
C84.NAMA,
C84.CCTY
FROM [email protected]_CMS_PRD C21,
[email protected]_CMS_PRD C22,
[email protected]_CMS_PRD C71,
[email protected]_CMS_PRD C81,
[email protected]_CMS_PRD C84,
(SELECT C21.PINO DN
FROM [email protected]_CMS_PRD C21,
GENERALINFO G
WHERE C21.INVD>=TO_DATE('01012011','MMDDYYYY')
AND C21.NCMP ='F555'
AND C21.PINO =G.G_DN(+)
AND G.G_DN IS NULL
) DNSTOFIND
WHERE C21.PINO =C22.PINO
AND DECODE(SUBSTR(TRIM(C22.ITEM),1,3),'PRD','Y','ASY','Y','SLA','Y','N')='Y'
AND C21.ORNO =C71.ORNO
AND C21.ORNO =C81.ORNO
AND C22.PONO =C81.PONO
AND C21.ORNO =C84.ORNO
AND C84.CTYP ='ST'
AND DNSTOFIND.DN =C21.PINO
ORDER BY C21.PINO,
C22.PONO;
歡迎來到StackOverflow。我希望你的真實SQL不會像你發佈的那樣間隔太大和格式不對。我做了一些編輯讓你開始，但大約10分鐘後試圖修復它，但放棄了。請編輯您的帖子，以在「C1 = C2，C3，C4」（注意它們所屬的空間）等條件之間提供適當的間距，以便線條正確折斷，然後將它們分開，以使其長度可讀。您可以通過在頁面中向下滾動來預覽帖子;預覽位於代碼編輯窗口下方。原來，你的帖子是不可讀的，可能無法獲得答案。 :) –
此外，在您的問題標題中的SHOUTING無法幫助您更快地獲得答案。 :)它只是讓閱讀變得更加困難。 –
對不起，這是更好嗎？還有你的意思是喊什麼？它只是說Oracle Query Tuning或者它應該是其他方式？ – Mario