如何重寫select子句中擺脫子查詢的

-2

Select 
Xyz, 
CASE 
    WHEN 'AEJ-DODGE-AC-' 
     ||measure IN 
     (SELECT child 
     FROM interim_dim_measures_mas 
     WHERE child LIKE 'AEJ-DODGE-AC%' 
     CONNECT BY prior child = parent 
     START WITH parent  = 'Total Revenue (GBS).1' 
    ) 
    THEN -1*CAST(datavalue AS FLOAT) 
    ELSE CAST(datavalue AS FLOAT) 
    END AS amount 
FROM interim_data_misbaej, 
    w_csrbrd 
WHERE LENGTH(period) = 3 
AND 'AEJ-BK-' 
    || book = region_book(+)

來源

2013-11-21 user3018037

這是一個非常不尋常的語法。你想用||完成什麼？施工？另外，爲什麼它有一個問題，有一個子查詢？最後，您現有的查詢是否真的可以正常工作？ – catfood

那'''部分不重要;子查詢執行5億次的問題並且導致性能下降;表interim_data_misbaej有450萬行，w_csrbrd有5000行;所以想知道從select子句中刪除子查詢的等效sql – user3018037

好吧，我發現這是一個Oracle問題，我沒有資格非常有幫助。但是我確實修復了標籤，所以也許別人會選擇它。 – catfood

可以使用LEFT JOIN迫使這只是一次運行，GROUP BY和COUNT，以確定是否匹配已經發現：

Select Xyz, 
     CASE 
     WHEN COUNT(m.child) THEN -1*CAST(datavalue AS FLOAT) 
     ELSE CAST(datavalue AS FLOAT) 
     END AS amount 
FROM interim_data_misbaej, w_csrbrd 
LEFT JOIN (
    SELECT child 
    FROM interim_dim_measures_mas 
    WHERE child LIKE 'AEJ-DODGE-AC%' 
    CONNECT BY prior child = parent 
    START WITH parent  = 'Total Revenue (GBS).1' 
) m ON ('AEJ-DODGE-AC-' || measure) = m.child 
WHERE LENGTH(period) = 3 
    AND 'AEJ-BK-' || book = region_book(+) 
GROUP BY Xyz, measure, datavalue

來源

2013-11-22 16:58:04 PinnyM

如何重寫select子句中擺脫子查詢的

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