在2個日期之間的日期聯接2個表

Question

我試圖在一個表中找到給定日期和時間的客戶位置，並更新另一個表。 我必須在發出信件時用正確的地址生成信件（PDF）。 客戶在表中有一個移動記錄，該記錄可以告訴他在給定日期和時間的位置。 例如，我們生成給客戶AAA的日期為2016年5月3日的信函。 它應該具有LocA的地址位置。 客戶BBB收到一封日期為05/22/2016的信件，並且該信件的位置應為LocE。 我需要更新CustomerLetter.AddressLocation從價值CustomerMovement.AddressLocation ，我似乎無法得到這個開始。

這是我的桌子。

CREATE global temporary TABLE CustomerLetter (CustomerID varchar2(6), AddressLocation varchar2(6), LetterDate date);
INSERT INTO CustomerLetter (CustomerID, AddressLocation, LetterDate) VALUES ('AAA', NULL, '2016-05-03');
INSERT INTO CustomerLetter (CustomerID, AddressLocation, LetterDate) VALUES ('AAA', NULL, '2016-05-05');
INSERT INTO CustomerLetter (CustomerID, AddressLocation, LetterDate) VALUES ('AAA', NULL, '2016-08-14');
INSERT INTO CustomerLetter (CustomerID, AddressLocation, LetterDate) VALUES ('BBB', NULL, '2016-05-02');
INSERT INTO CustomerLetter (CustomerID, AddressLocation, LetterDate) VALUES ('BBB', NULL, '2016-05-29');
INSERT INTO CustomerLetter (CustomerID, AddressLocation, LetterDate) VALUES ('BBB', NULL, '2016-07-22');
INSERT INTO CustomerLetter (CustomerID, AddressLocation, LetterDate) VALUES ('CCC', NULL, '2016-03-06');
INSERT INTO CustomerLetter (CustomerID, AddressLocation, LetterDate) VALUES ('CCC', NULL, '2016-11-25');
commit;
CREATE global temporary TABLE CustomerMovement (CustomerID varchar2(6), ActionDate date, AddressLocation varchar2(6));
INSERT INTO CustomerMovement (CustomerID, AddressLocation, ActionDate) VALUES ('AAA', 'locA', TO_DATE('2016-05-02 09:05:00', 'yyyy-mm-dd HH24:MI:SS'));
INSERT INTO CustomerMovement (CustomerID, AddressLocation, ActionDate) VALUES ('AAA', 'locA', TO_DATE('2016-05-04 14:05:00', 'yyyy-mm-dd HH24:MI:SS'));
INSERT INTO CustomerMovement (CustomerID, AddressLocation, ActionDate) VALUES ('AAA', 'locB', TO_DATE('2016-05-04 22:00:00', 'yyyy-mm-dd HH24:MI:SS'));
INSERT INTO CustomerMovement (CustomerID, AddressLocation, ActionDate) VALUES ('AAA', 'locE', TO_DATE('2016-07-02 20:00:00', 'yyyy-mm-dd HH24:MI:SS'));
INSERT INTO CustomerMovement (CustomerID, AddressLocation, ActionDate) VALUES ('AAA', 'locA', TO_DATE('2016-06-03 06:10:00', 'yyyy-mm-dd HH24:MI:SS'));
INSERT INTO CustomerMovement (CustomerID, AddressLocation, ActionDate) VALUES ('BBB', 'locE', TO_DATE('2016-05-10 03:00:00', 'yyyy-mm-dd HH24:MI:SS'));
INSERT INTO CustomerMovement (CustomerID, AddressLocation, ActionDate) VALUES ('BBB', 'locF', TO_DATE('2016-06-01 03:00:00', 'yyyy-mm-dd HH24:MI:SS'));
INSERT INTO CustomerMovement (CustomerID, AddressLocation, ActionDate) VALUES ('CCC', 'locA', TO_DATE('2016-10-10 03:00:00', 'yyyy-mm-dd HH24:MI:SS'));
INSERT INTO CustomerMovement (CustomerID, AddressLocation, ActionDate) VALUES ('CCC', 'locA', TO_DATE('2016-12-03 03:00:00', 'yyyy-mm-dd HH24:MI:SS'));
commit;

Answer 1

在UPDATE語句中使用子查詢來查詢每個字母的適當addressLocation值。

使用您在問題中發布的表格和數據，結果將如下所示：

update CustomerLetter cl
SET addresslocation = ( SELECT cm.addressLocation  
                        FROM   CutomerMovement cm
                        WHERE  cm.customerID = cl.customerID
                        AND    cm.actionDate <= cl.letterDate
                        ORDER BY cm.actionDate DESC
                        FETCH FIRST 1 ROW ONLY );

對於每個字母，找到在letterDate 之前發生的客戶移動。 然后，使用最近移動中的addressLocation 。

如果信函在信函日期之前沒有客戶移動記錄，則該信函的地址位置將為null 。