从SQL查询重复

Question

我有一个从多个连接中检索的数据集。 我在我的语句中使用了SELECT DISTINCT，但我仍然在结果集中看到重复项。 这是代码：

SELECT DISTINCT Account
, PayoffAmtDOL as 'Payoff Amount DOL'
, PayoffAmtLOG as 'Payoff Amount LOG'
, PayoffAmountLive as 'Payoff Amount Live'
, [Difference]
, PrincipalBalance as 'Principal Balance'
, CreationDate as 'Date Entered System'
, CACSState as 'CACS State at Entry'
, PaymentsMade AS 'Payments Made'
, TotalPaymentAmount as 'Total Payment Amount'
, 'Liquidation Percentage' = CASE WHEN PayoffAmountLive = 0 THEN 1
                            WHEN ISNULL([Difference],0) = ISNULL(PayoffAmtDOL, 0) THEN 1
                            WHEN ISNULL([Difference],0) < 0 AND ISNULL(PayoffAmtDOL, 0) > 0 THEN 0
                            WHEN ISNULL([Difference],0) > 0 AND ISNULL(PayoffAmtDOL, 0) < 0 THEN 1
                            WHEN ISNULL([Difference],0) > ISNULL(PayoffAmtDOL, 0) THEN 1
                            WHEN [Difference] > 0 AND ISNULL(PayoffAmtDOL, 0) = 0 THEN 1
                            WHEN ISNULL(PayoffAmtDOL, 0) = 0 THEN 0
                            ELSE ISNULL([Difference],0)/ISNULL(PayoffAmtDOL, 0) END
          , Cnt = 1
FROM 
(
SELECT DISTINCT a.Account,
       c.PayoffAmtDOL,
       c.PayoffAmtLOG,
       (ISNULL(c.PayoffAmtCACS, cacs.payoff_amt)) as 'PayoffAmountLive',
       (ISNULL(c.PayoffAmtDOL, 0) - (ISNULL(c.PayoffAmtCACS , ISNULL(cacs.payoff_amt, 0)))) as 'Difference',
       c.PrincipalBalance,
       c.CreationDate,
       c.CACSState,
       (SELECT COUNT(PaymentID)
        FROM tblATLPaymentInfo p
        WHERE p.AccountID = a.AccountID
          AND CONVERT(DATETIME, CONVERT(VARCHAR(10), p.CreationDate, 101)) >=  '1/1/2014'
          AND CONVERT(DATETIME, CONVERT(VARCHAR(10), p.CreationDate, 101)) <= '3/27/2014'
        ) as 'PaymentsMade',
         (SELECT SUM(PaymentAmount)
        FROM tblATLPaymentInfo p
        WHERE p.AccountID = a.AccountID
          AND CONVERT(DATETIME, CONVERT(VARCHAR(10), p.CreationDate, 101)) >= '1/1/2014'
          AND CONVERT(DATETIME, CONVERT(VARCHAR(10), p.CreationDate, 101)) <= '3/27/2014'
        ) as 'TotalPaymentAmount'

FROM tblATLAcctInfo a
RIGHT JOIN tblATLClaimInfo c
    ON c.AccountID = a.AccountID
LEFT JOIN SCFLOKYDCMSQL03.CACS_DM.dbo.Cacs_Info cacs
    ON cacs.Account = a.Account
WHERE CONVERT(DATETIME, CONVERT(VARCHAR(10), c.CreationDate, 101)) >= '1/1/2014'
    AND CONVERT(DATETIME, CONVERT(VARCHAR(10), c.CreationDate, 101)) <=  '3/27/2014'
    AND c.ClaimTypeID = (SELECT  DISTINCT ClaimTypeID FROM tblATLClaimType WHERE ClaimType = 'N02 - Claims')
) a
ORDER BY Account

以下是重复行的示例：

AccountID   DateEntered
123     01/19/2014
123     01/21/2014
345     02/1/2014
345     02/10/2014

两者之间的差异似乎是输入的日期。 也许选择Row_Number（）然后删除更晚的日期可能是一个解决方案

Answer 1

DISTINCT不应该返回多行..每行应该至少有一列不同，不是吗？ 对于字符数据，有时可能会被不可见的差异所欺骗，例如尾随空格。 但不确定这是否是这种情况。

你能举一个重复行的例子吗？

好的，我看到了你的编辑。 您必须选择要显示的日期。 试试这个以获得每个AccountID的最早日期：

 SELECT AccountID, MIN(DateEntered) AS DateEntered
 FROM ....
 GROUP BY AccountID
 ORDER BY AccountID

您可以在SELECT中添加更多列，只要它们不同，就不会获得更多行。

如果需要，可以向选择中添加COUNT（*）以获取分组的行数。

Answer 2

DISTINCT将仅拒绝完全重复的行，每个ID上的DateEntered不同。 如果你想要最新的，请使用Max（DateEntered）