Oracle SQL - 通過多個連接獲取Max Date

Question

我想我可能會反思這一點，但是我在嘗試通過Oracle數據庫中的多個連接以及幾個where子句找到最大日期時遇到問題。我發現了很多簡單的最大查詢的例子，但沒有特別的例子。查詢工作正常，如果我添加一行來查找特定日期之上的所有記錄（只返回少數結果）。但是，我想自動從帳單表中獲取所有記錄的最新日期。這個數據庫有一個額外的表格，其中存儲了實際帳單數量，因此增加了另一個層次。

SELECT p.purchase_id, p.account_id, b.bill_date, bp.current_amount 
FROM Purchases p 
JOIN Bill_Purchases bp ON p.purchase_id = bp.purchase_id 
JOIN Bills b ON bp.bill_id = b.bill_id 
--NEED TO GET MOST RECENT DATE FROM BILL TABLE FOR EACH BILL 
WHERE p.type != 'CASH' 
AND bp.amount > '100.00' 
AND p.status = 'Approved' 
AND p.purchase_id IN (... list of purchases ...); 

我已經嘗試在他們的最大功能做子查詢，但我沒有任何運氣。每個查詢返回與原始查詢相同數量的記錄。我將如何重新安排這個查詢來檢索所有必要的列和where子句，同時還將此限制爲僅最近一次收費的購買行爲？

Answer 1

我在發佈後幾乎找到了這個工作，這是我的一個愚蠢的錯誤。最大函數的數據需要在account_id上加入，而不是bill_id。

Answer 2

嘗試使用低於這個

SELECT p.purchase_id, p.account_id, b.bill_date, bp.current_amount 
FROM Purchases p 
JOIN Bill_Purchases bp ON p.purchase_id = bp.purchase_id 
JOIN ( SELECT bill_id, MAX(bill_date) bill_date 
     FROM Bills 
     GROUP BY bill_id 
    )b ON bp.bill_id = b.bill_id 
WHERE p.type != 'CASH' 
AND bp.amount > '100.00' 
AND p.status = 'Approved' 
AND p.purchase_id IN (... list of purchases ...); 

Answer 3

您可能需要使用解決功能Rank()這個問題，

SELECT p.purchase_id, p.account_id, , bp.current_amount, RANK() OVER (partition by b.bill_id order by b.bill_date) as max_bill_date 
FROM Purchases p 
JOIN Bill_Purchases bp ON p.purchase_id = bp.purchase_id 
JOIN Bills b ON bp.bill_id = b.bill_id 
--NEED TO GET MOST RECENT DATE FROM BILL TABLE FOR EACH BILL 
WHERE max_bill_date = 1 
AND p.type != 'CASH' 
AND bp.amount > '100.00' 
AND p.status = 'Approved'`enter code here` 
AND p.purchase_id IN (... list of purchases ...); 

Answer 4

做這兩種工作的嗎？

WITH data as (
    SELECT 
     p.purchase_id, p.account_id, b.bill_date, bp.current_amount, 
    FROM 
     Purchases p 
     INNER JOIN Bill_Purchases bp ON p.purchase_id = bp.purchase_id 
     INNER JOIN Bills b ON b.bill_id = bp.bill_id 
    WHERE p.type <> 'CASH' 
    AND bp.amount > '100.00' 
    AND p.status = 'Approved' 
    AND p.purchase_id IN (... list of purchases ...) 
), most_recent as (
    SELECT max(bill_date) as bill_date FROM data 
) 
SELECT * 
FROM data 
WHERE bill_date = (select bill_date from most_recent); 


SELECT purchase_id, account_id, bill_date, current_amount 
FROM (
    SELECT 
     p.purchase_id, p.account_id, b.bill_date, bp.current_amount, 
     dense_rank() over (order by b.bill_date desc) as dr 
    FROM 
     Purchases p 
     INNER JOIN Bill_Purchases bp ON p.purchase_id = bp.purchase_id 
     INNER JOIN Bills b ON b.bill_id = bp.bill_id 
    WHERE p.type <> 'CASH' 
    AND bp.amount > '100.00' 
    AND p.status = 'Approved' 
    AND p.purchase_id IN (... list of purchases ...) 
) data 
WHERE dr = 1;