如何获取SQL Server中每个组/分区的最大行数？

Question

我正在使用SQL Server 2005.我有一个付款表，其中包含付款ID，用户ID和时间戳。 我想找到每个用户的最新付款。 这很容易搜索并找到答案。 我还想知道的是，最近的付款是否是用户的第一次付款。

我有以下将为每个用户的付款编号：

SELECT
    p.payment_id,
    p.user_id,
    ROW_NUMBER() OVER (PARTITION BY p.user_id ORDER BY p.payment_date) AS paymentNumber
FROM
    payment p

我没有进行精神飞跃，然后让我选择每个用户最高的paymentNumber。 如果我使用MAX（paymentNumber）将上面的内容用作子选择，然后按user_id进行分组，则会丢失我需要的payment_id。 但是，如果我还将payment_id添加到group by子句中，那么每次付款我都会返回一行。 我敢肯定我忽视了这一点。 有帮助吗？

Answer 1

尝试这个：

SELECT a.*, CASE WHEN totalPayments>1 THEN 'NO' ELSE 'YES' END IsFirstPayment
  FROM(
                SELECT  p.payment_id,     
                                p.user_id,     
                                ROW_NUMBER() OVER (PARTITION BY p.user_id ORDER BY p.payment_date DESC) AS paymentNumber,
                                SUM(1) OVER (PARTITION BY p.user_id) AS totalPayments
                    FROM payment p 
            ) a
WHERE   paymentNumber = 1       

Answer 2

再做同样的事情。

SELECT
    p.payment_id,
    p.user_id,
    ROW_NUMBER() OVER (PARTITION BY p.user_id ORDER BY p.payment_date) AS paymentNumber,
    ROW_NUMBER() OVER (PARTITION BY p.user_id ORDER BY p.payment_date DESC) AS reversePaymentNumber,
FROM
    payment p

现在最近的付款有reversePaymentNumber 1，付款数量是paymentNumber。

Answer 3

; with cte as (
SELECT
    p.payment_id,
    p.user_id,
    ROW_NUMBER() OVER (PARTITION BY p.user_id ORDER BY p.payment_date desc) AS paymentNumber
FROM
    payment p
) select * from cte where paymentNumber = 1

Answer 4

我认为这种方式不太酷

; with maxp as
(
    select
        p.user_id,
        max(p.payment_date) as MaxPaymentDate
    from payment p
    group by p.userid
),
nump as
(
    select
        p.payment_id,     
        p.user_id,     
        p.payment_date,
        ROW_NUMBER() OVER (PARTITION BY p.user_id ORDER BY p.payment_date) AS paymentNumber 
    FROM payment p
),
a as
(
select
    nump.payment_id,
    nump.user_id,
    nump.paymentNumber
    case when maxp.MaxPaymentDate is null then 'Old' else 'New' end as NewState
from nump
    left outer join maxp
        on nump.user_id=maxp.user_id
            and nump.payment_date=maxp.MaxPaymentDate
)

select
*
from a
where NewState='New'

Answer 5

SELECT * FROM (
        SELECT ROW_NUMBER() OVER(PARTITION BY OS.ContactId ORDER BY OS.Date ASC) AS FirstRow#,
        ROW_NUMBER() OVER(PARTITION BY OS.ContactId ORDER BY OS.Date DESC) AS LastRow#,
        OS.Contactid,CONVERT(VARCHAR,OS.Date,106) 'Purchase Month',
        OS.ProductId 'MyCII Subscription/Directory', OS.Charges 'Amount(INR)',OS.Date 'RAWDate'
        FROM tblOnlineServices OS
        WHERE Date IS NOT NULL AND Contactid IN('C000013112','C000010859') 
    ) FirstPurchase 
    WHERE FirstRow# = 1 OR LastRow# = 1
    ORDER BY Contactid, RAWDate

Answer 6

这个怎么样？

SELECT
    p.user_id,
    MAX(p.payment_date) as lastPayment,
    CASE COUNT(p.payment_id) WHEN 1 THEN 1 ELSE 0 END as isFirstPayment
FROM
    payment p
GROUP BY
    p.user_id