SQL - 按电子邮件和最新日期分组

Question

我有一个 SQL 查询，它应该向我显示每位客户的最后一次付款，但它向我显示了所有客户所做的每笔付款。我为此花了一天时间，我即将放弃。我想尝试通过客户电子邮件对我的报告进行分组，然后从每组 customerpayments 中返回每组最近的日期。这应该会在一份报告中向我显示每位客户最近的付款。

我正在从多个表中提取信息。理论上，客户可以拥有相同的姓名、号码或支付相同的金额。但其中唯一的字段是电子邮件。客户也可以升级他们的帐户，因此客户进行的一组付款可能不都是相同的值。因此，如果我们返回最近的日期，它将显示他们当前的最后一次付款。

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SELECT 
    AccountTypes.Name AS AccountType, 
    CONVERT(nvarchar, PaymentHistory.DateCreated, 23) AS Prev_Billing_Date,
    PaymentHistory.Amount AS Amount, 
    Users.FirstName AS FName, 
    Users.LastName AS LName, 
    Users.Phone AS Phone, 
    Users.Email AS Email
FROM 
    AccountTypes 
INNER JOIN 
    Accounts 
INNER JOIN 
    AccountStatus ON Accounts.StatusID = AccountStatus.ID 
INNER JOIN 
    PaymentHistory ON Accounts.ID = PaymentHistory.AccountID 
            ON AccountTypes.ID = Accounts.AccountTypeID 
INNER JOIN 
    Users 
INNER JOIN 
    UserAccounts ON Users.ID = UserAccounts.UserID 
            ON Accounts.ID = UserAccounts.AccountID
WHERE 
    (UserAccounts.IsOwner = 1) AND 
    (AccountStatus.Name = 'Paid') AND 
    (Accounts.AccountTypeID = 2 OR 
     Accounts.AccountTypeID = 3 OR 
     Accounts.AccountTypeID = 4 OR 
     Accounts.AccountTypeID = 5)
GROUP BY
    AccountTypes.Name, 
    PaymentHistory.DateCreated,
    PaymentHistory.Amount, 
    Users.FirstName, 
    Users.LastName, 
    Users.Phone, 
    Users.Email
ORDER BY 
    AccountType DESC, Email, Prev_Billing_Date DESC;

Answer 1

您可以使用row_number() 和partition by 来实现您想要的。你不需要使用GROUP BY，因为你没有使用任何聚合函数。

SELECT t1.* FROM 
    (SELECT 
        AccountTypes.Name AS AccountType, 
        CONVERT(nvarchar, PaymentHistory.DateCreated, 23) AS Prev_Billing_Date,
        PaymentHistory.Amount AS Amount, 
        Users.FirstName AS FName, 
        Users.LastName AS LName, 
        Users.Phone AS Phone, 
        Users.Email AS Email,
        ROW_NUMBER() over (PARTITION BY Users.Email ORDER BY PaymentHistory.DateCreated DESC) as rn
    FROM AccountTypes 
    INNER JOIN Accounts ON AccountTypes.ID = Accounts.AccountTypeID 
    INNER JOIN AccountStatus ON Accounts.StatusID = AccountStatus.ID 
    INNER JOIN PaymentHistory ON Accounts.ID = PaymentHistory.AccountID                     
    INNER JOIN UserAccounts ON Accounts.ID = UserAccounts.AccountID
    INNER JOIN Users ON Users.ID = UserAccounts.UserID      
    WHERE 
        UserAccounts.IsOwner = 1 AND 
        AccountStatus.Name = 'Paid' AND 
        Accounts.AccountTypeID IN (2,3,4,5)
    ) t1
WHERE t1.rn = 1
ORDER BY 
    t1.AccountType DESC, t1.Email, t1.Prev_Billing_Date DESC;