Question

还有其他写方法吗？如果“应用程序”表中的“信用卡ID”为NULL，则从“终止的信用卡”表中加入“信用卡ID”。谢谢，

这是错误：

消息4104，第16级，状态1，第18行
不能绑定多部分标识符“ TC.CreditCardID”。

代码：

SELECT DISTINCT 
    prg.Title AS Program, a.Patientid,
    a. Applicationid,
    PT.MCC,
    PT.MerchantName,
    PT.MerchantCity, PT.MerchantState,
    PT.MerchantZip,
    PT.SettlementTransactionID,
    CONVERT(DATE, PT.SettlementDate) AS SettlementDate
    ABS(PT.Amount) as TransactionAmount
FROM 
    [dbo].[StagingSettlements] PT  
LEFT JOIN 
    dbo.Application a ON PT.[CustomId] = ISNULL(a.CreditCardId, TC.CreditCardID)
LEFT JOIN 
    dbo.TerminatedCreditCard TC ON TC.ApplicationId = a.ApplicationId

Answer 1

几点：

您似乎没有在结果集中使用信用卡号，所以我不清楚您为什么要使用它？
您需要将NULL检查放入TerminatedCreditCard的联接中。之所以收到此错误，是因为您尝试在加入TerminatedCreditCard之前先对其进行引用。

下面的SQL应该可以解决您的问题，我不确定StagingSettlements和应用程序之间的连接条件是什么，所以我刚刚放入了一个占位符，需要对其进行更新，我还添加了一个'CreditCardId '进行选择：

SELECT Distinct 
         prg.Title as Program
        ,a.Patientid
        ,a.Applicationid
        ,PT.MCC
        ,PT.MerchantName
        ,PT.MerchantCity
        ,PT.MerchantState
        ,PT.MerchantZip
        ,PT.SettlementTransactionID
        ,convert(Date,PT.SettlementDate) as SettlementDate
        ,ABS(PT.Amount) as TransactionAmount
        ,COALESCE(TC.CreditCardId, a.CreditCardId) as CreditCardId
FROM    [dbo].[StagingSettlements] PT  
            LEFT JOIN dbo.Application a
                ON      a.<applicationid> = PT.<applicationid>
            LEFT JOIN dbo.TerminatedCreditCard TC      
                ON      TC.ApplicationId = a.ApplicationId 
                    AND a.CreditCardId IS NULL

Answer 2

您可以更改联接precedence来获取此信息：

FROM [dbo].[StagingSettlements] AS PT  
LEFT JOIN ( dbo.Application AS a
    LEFT JOIN dbo.TerminatedCreditCard AS TC on TC.ApplicationId = a.ApplicationId )
        ON PT.[CustomId] = ISNULL( a.CreditCardId, TC.CreditCardID )

上面加上括号会导致首先对Application至TerminatedCreditCard的连接进行求值，然后将结果连接至StagingSettlements。

SQL：联接条件中的ISNULL

2 个答案: