第一期的日期是加入日期。顾客必须分期付款。每月分期付款。因此,在11个月后,客户有资格购买产品节省的金额。因此到期日为加入之日起11个月。加入日期:2016年9月12日到期日:2017年7月12日
如果客户在预定日期或当月任何一天内付款,到期日不延长,否则到期日延长。
Scenario 1: Pays on time
------------------------
Joining date: 12/Sep/2016
Expected output: 12/Jul/2017
Joining Date 12/Sep/2016 Inst No Payment Date Actual Date payment Considered Month 1 12/Sep/2016 12/Sep/2016 Sep 2016 2 05/Oct/2016 12/Oct/2016 Oct 2016 3 21/Nov/2016 12/Nov/2016 Nov 2016 4 12/Dec/2016 12/Dec/2016 Dec 2016 5 02/Jan/2017 12/Jan/2017 Jan 2017 6 02/Feb/2017 12/Feb/2017 Feb 2017 7 06/Mar/2017 12/Mar/2017 Mar 2017 8 06/Apr/2017 12/Apr/2017 Apr 2017 9 01/May/2017 12/May/2017 May 2017 10 07/Jun/2017 12/Jun/2017 Jun 2017 Maturity Date 12/Jul/2017
方案1
Scenario 2: when payments paid with delay
-----------------------------------------
Joining date: 12/Sep/2016
Expected output: 12/Sep/2017
场景2
Joining Date 12/Sep/2016 Inst No Payment Date Actual Date Payment Considered Month 1 12/Sep/2016 12/Sep/2016 Sep 2016 2 05/Oct/2016 12/Oct/2016 Oct 2016 3 21/Nov/2016 12/Nov/2016 Nov 2016 4 02/Feb/2017 12/Dec/2016 Feb 2017 5 02/Feb/2017 12/Jan/2017 Mar 2017 6 06/Mar/2017 12/Feb/2017 Apr 2017 7 06/Mar/2017 12/Mar/2017 May 2017 8 01/Jun/2017 12/Apr/2017 Jun 2017 9 01/Jun/2017 12/May/2017 Jul 2017 10 07/Aug/2017 12/Jun/2017 Aug 2017 Maturity Date 12/Sep/2017
你的问题不清楚你想要达到什么目的。但是,我从你们的两个例子中了解到的是,到期日应该和分期付款的延迟时间一样推后几个月。
甚至你的小提琴手场景也不清楚。有了这一点了解,我想出了下面的T-SQL来解决你的问题:
-- Schema generation
CREATE TABLE [dbo].[Payment](
[InsNo] [int] PRIMARY KEY NOT NULL,
[ReceiptDate] [datetime] NULL,
[ScheduledDate] [datetime] NULL,
[ConsideredMonth] DATETIME NULL,
) ON [PRIMARY]
GO
INSERT INTO [Payment]([InsNo], [ReceiptDate], [ScheduledDate])
VALUES(1, '2016-09-12 00:00:00', '2016-09-12 00:00:00');
INSERT INTO [Payment]([InsNo], [ReceiptDate], [ScheduledDate])
VALUES(2, '2016-10-05 00:00:00', '2016-10-12 00:00:00');
INSERT INTO [Payment]([InsNo], [ReceiptDate], [ScheduledDate])
VALUES(3, '2016-11-21 00:00:00', '2016-11-12 00:00:00');
INSERT INTO [Payment]([InsNo], [ReceiptDate], [ScheduledDate])
VALUES(4, '2017-02-02 00:00:00', '2016-12-12 00:00:00');
INSERT INTO [Payment]([InsNo], [ReceiptDate], [ScheduledDate])
VALUES(5, '2017-02-02 00:00:00', '2016-01-12 00:00:00');
INSERT INTO [Payment]([InsNo], [ReceiptDate], [ScheduledDate])
VALUES(6, '2017-02-02 00:00:00', '2016-02-12 00:00:00');
INSERT INTO [Payment]([InsNo], [ReceiptDate], [ScheduledDate])
VALUES(7, '2017-03-06 00:00:00', '2016-03-12 00:00:00');
INSERT INTO [Payment]([InsNo], [ReceiptDate], [ScheduledDate])
VALUES(8, '2017-03-06 00:00:00', '2016-04-12 00:00:00');
INSERT INTO [Payment]([InsNo], [ReceiptDate], [ScheduledDate])
VALUES(9, '2017-06-01 00:00:00', '2016-05-12 00:00:00');
INSERT INTO [Payment]([InsNo], [ReceiptDate], [ScheduledDate])
VALUES(10, '2017-06-01 00:00:00', '2016-06-12 00:00:00');
GO
-- Solution using Cursor
DECLARE @receiptDate DATETIME
,@lastInstForDate DATETIME
DECLARE @insNo INT
DECLARE _paymentsCursor CURSOR FAST_FORWARD
FOR
SELECT p.InsNo
,p.ReceiptDate
FROM Payment p
ORDER BY
p.InsNo
OPEN _paymentsCursor
FETCH NEXT FROM _paymentsCursor INTO
@insNo, @receiptDate
WHILE @@FETCH_STATUS = 0
BEGIN
SELECT @lastInstForDate = p.ConsideredMonth
FROM Payment p
WHERE p.InsNo = @insNo - 1
IF DATEADD(MONTH ,1 ,@lastInstForDate) > @receiptDate
UPDATE Payment
SET ConsideredMonth = DATEADD(MONTH ,1 ,@lastInstForDate)
WHERE InsNo = @insNo
ELSE
UPDATE Payment
SET ConsideredMonth = CAST(CAST(YEAR(ReceiptDate) AS VARCHAR(4)) + RIGHT('0' + CAST(MONTH(ReceiptDate) AS VARCHAR(2)) ,2) + '01' AS DATETIME)
WHERE InsNo = @insNo
FETCH NEXT FROM _paymentsCursor INTO
@insNo, @receiptDate
END
CLOSE _paymentsCursor
DEALLOCATE _paymentsCursor
DECLARE @lastPaymentDate DATETIME
DECLARE @maturityDate DATETIME
SELECT @maturityDate = DATEADD(month, 1, MAX(p.ConsideredMonth)), @lastPaymentDate = MAX(p.ReceiptDate) FROM dbo.Payment p
SET @maturityDate = CAST(CAST(YEAR(@maturityDate) AS VARCHAR(4)) + RIGHT('0' + CAST(MONTH(@maturityDate) AS VARCHAR(2)) ,2) + RIGHT('0' + CAST(DAY(@lastPaymentDate) AS VARCHAR(2)) ,2) AS DATETIME)
SET @maturityDate = DATEADD(DAY, 1, @maturityDate)
SELECT @maturityDate