如何获取SQL Server中每个组/分区的最大行数?

时间:2011-02-04 22:19:06

标签: sql sql-server sql-server-2005 tsql

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。

我有以下内容对每位用户的付款进行编号:

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

我没有进行精神上的飞跃,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。有什么帮助吗?

6 个答案:

答案 0 :(得分:28)

试试这个:

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       

答案 1 :(得分:11)

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,付款次数为paymentNumber。

答案 2 :(得分: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

答案 3 :(得分:1)

我认为不太酷的方式

; 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'

答案 4 :(得分:1)

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

答案 5 :(得分:0)

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