3

我们已经JCC将抽取的数据从 馈送Oracle到SQL Server 2016。由于一些未知的原因，历史表中存在具有相同开始和结束时间的重复项。怎么会发生？我试图用条件更新记录SET Column = Column。在那种情况下，我有 2 条记录，其中所有字段都相同，但开始时间和结束时间不同。有相同的日期时间怎么会发生？

更新： 在此处输入图像描述

DDL：

CREATE TABLE [dbo].[LEASES](
    [LEASE_NUMBER] [CHAR](7) NOT NULL,
    [CREDIT_DECISION_CODE] [CHAR](1) NULL,
    [LEASE_APPLICATION] [CHAR](7) NULL,
    [ACCOUNT_NUMBER] [CHAR](8) NULL,
    [CELLULAR_NUMBER] [CHAR](10) NULL,
    [DEALER_CODE] [CHAR](5) NULL,
    [USERNAME] [CHAR](12) NULL,
    [LEASE_DATE] [DATETIME2](7) NULL,
    [NEW_USED_FLAG] [CHAR](1) NULL,
    [MANUFACTURER_CODE] [CHAR](6) NULL,
    [MODEL] [CHAR](10) NULL,
    [SERIAL_NUMBER_ELECTRONIC] [INT] NULL,
    [SERIAL_NUMBER_MECHANICAL] [CHAR](10) NULL,
    [CONTROL_HEAD] [CHAR](12) NULL,
    [LEASE_TERM] [SMALLINT] NULL,
    [LESSEE_CITY] [CHAR](17) NULL,
    [LESSEE_ADDRESS_1] [CHAR](30) NULL,
    [LESSEE_ADDRESS_2] [CHAR](30) NULL,
    [LESSEE_STATE] [CHAR](2) NULL,
    [LESSEE_ZIP_CODE] [CHAR](9) NULL,
    [LESSEE_NAME] [CHAR](30) NULL,
    [KEY_NAME] [CHAR](12) NULL,
    [BASE_PAYMENT] [DECIMAL](10, 2) NULL,
    [MONTHLY_SALES_TAX] [DECIMAL](10, 2) NULL,
    [INSURANCE] [DECIMAL](10, 2) NULL,
    [MONTHLY_PAYMENT] [DECIMAL](10, 2) NULL,
    [SECURITY_DEPOSIT] [DECIMAL](10, 2) NULL,
    [INVOICES_GENERATED_COUNT] [SMALLINT] NULL,
    [DATE_LAST_INVOICED] [DATETIME] NULL,
    [DATE_LAST_LATE_FEE] [DATETIME] NULL,
    [SECURITY_DEPOSITS_INVOICED] [DECIMAL](10, 2) NULL,
    [SECURITY_DEPOSITS_REFUNDED] [DECIMAL](10, 2) NULL,
    [ADVANCE_RENT] [DECIMAL](10, 2) NULL,
    [ADVANCE_SALES_TAX] [DECIMAL](10, 2) NULL,
    [TOTAL_ADVANCE_PAYMENT] [DECIMAL](10, 2) NULL,
    [AUTO_LEASE_EXPIRATION_DATE] [CHAR](4) NULL,
    [PAYMENTS_REMAINING] [SMALLINT] NULL,
    [PV_PAYMENTS_REMAINING] [DECIMAL](10, 2) NULL,
    [TAX_RATE] [DECIMAL](10, 4) NULL,
    [TAX_STATE] [CHAR](2) NULL,
    [LEASE_FACTOR] [DECIMAL](10, 4) NULL,
    [AMOUNT_FINANCED] [DECIMAL](10, 2) NULL,
    [REMARKS] [CHAR](60) NULL,
    [VOUCHER_NUMBER] [CHAR](12) NULL,
    [BILL_METHOD_ADVANCE] [CHAR](1) NULL,
    [FINANCING_PACKAGE] [INT] NULL,
    [BUYOUT_AMOUNT] [DECIMAL](10, 2) NULL,
    [BUYOUT_DATE] [DATETIME] NULL,
    [DEPRECIATION_MONTHS] [SMALLINT] NULL,
    [SALVAGE_VALUE] [DECIMAL](10, 2) NULL,
    [LAST_DEPRECIATION_DATE] [DATETIME] NULL,
    [LAST_DEPRECIATION_AMOUNT] [DECIMAL](10, 2) NULL,
    [ACCUMULATED_DEPRECIATION] [DECIMAL](10, 2) NULL,
    [BILL_METHOD_BUYOUT] [CHAR](1) NULL,
    [BUYOUT_INVOICED] [CHAR](1) NULL,
    [RECEIVED_DATE] [DATETIME] NULL,
    [LEASE_PROGRAM] [CHAR](5) NULL,
    [PAYMENTS_INCLUDED_ADVANCE] [SMALLINT] NULL,
    [SALESPERSON_CODE] [CHAR](5) NULL,
    [UNGUARANTEED_RESIDUAL_VALUE] [DECIMAL](10, 2) NULL,
    [UNEARNED_INCOME] [DECIMAL](10, 2) NULL,
    [DIRECT_COST] [DECIMAL](10, 2) NULL,
    [AMORTIZABLE_UNEARNED_INCOME] [DECIMAL](10, 2) NULL,
    [AMORTIZED_FLAG] [CHAR](1) NULL,
    [RESIDUAL_VALUE_PERCENTAGE] [DECIMAL](10, 4) NULL,
    [MINIMUM_LEASE_PAYMENTS] [DECIMAL](10, 2) NULL,
    [IMPLICIT_MONTHLY_INTEREST_RATE] [DECIMAL](10, 8) NULL,
    [AP_POSTED_FLAG] [CHAR](1) NULL,
    [AP_POSTED_DATE] [DATETIME] NULL,
    [CAPITALIZED_LEASE_FLAG] [CHAR](1) NULL,
    [LEASE_STATUS] [CHAR](1) NULL,
    [GROSS_INVESTMENT] [DECIMAL](10, 2) NULL,
    [ADVANCE_BILLED_FLAG] [CHAR](1) NULL,
    [AP_VOUCHER_NUMBER] [CHAR](12) NULL,
    [BANK_PACKAGE] [CHAR](5) NULL,
    [INSURANCE_BINDER] [CHAR](1) NULL,
    [CURRENT_BUYOUT] [DECIMAL](10, 2) NULL,
    [LEASE_AGE_YEARS] [SMALLINT] NULL,
    [GUARANTOR_NAME] [CHAR](30) NULL,
    [GUARANTOR_ADDRESS_LINE_1] [CHAR](30) NULL,
    [GUARANTOR_ADDRESS_LINE_2] [CHAR](30) NULL,
    [GUARANTOR_CITY] [CHAR](17) NULL,
    [GUARANTOR_STATE] [CHAR](2) NULL,
    [GUARANTOR_ZIP] [CHAR](9) NULL,
    [GUARANTOR_TELEPHONE] [CHAR](18) NULL,
    [GUARANTOR_SS_NUMBER] [CHAR](9) NULL,
    [GUARANTOR] [CHAR](30) NULL,
    [BILL_CYCLES_DEFER] [INT] NULL,
    [REVENUE_ACCOUNT] [CHAR](5) NULL,
    [INVOICE_TYPE] [CHAR](5) NULL,
    [CORRESPONDENCE_FLAG] [CHAR](1) NULL,
    [DOWN_PAYMENT] [DECIMAL](10, 2) NULL,
    [ADVANCE_INSURANCE] [DECIMAL](10, 2) NULL,
    [ORIGINAL_EQUIPMENT_COST] [DECIMAL](10, 2) NULL,
    [SERVICING_DEALER_CODE] [CHAR](5) NULL,
    [DEALER_BUYOUT_DATE] [DATETIME] NULL,
    [LEASE_OWNER_CODE] [CHAR](5) NULL,
    [LEASE_OWNER_DATE] [DATETIME] NULL,
    [VENDOR_CODE] [CHAR](5) NULL,
    [SPLIT_FUNDING_COUNT] [SMALLINT] NULL,
    [DEALER_AMOUNT] [DECIMAL](10, 2) NULL,
    [VENDOR_AMOUNT] [DECIMAL](10, 2) NULL,
    [SALESPERSON_AMOUNT] [DECIMAL](10, 2) NULL,
    [DEALER_OFFICE] [SMALLINT] NULL,
    [ASSESSMENT_YEAR] [SMALLINT] NULL,
    [PROPERTY_TAX_RATE] [DECIMAL](10, 4) NULL,
    [ASSESSMENT_FACTOR] [DECIMAL](10, 4) NULL,
    [MONTHLY_PROPERTY_TAX] [DECIMAL](10, 2) NULL,
    [MANAGER_CODE] [CHAR](5) NULL,
    [DEALER_BUYOUT_PROGRAM] [CHAR](5) NULL,
    [SHARED_RESID_METHOD] [CHAR](1) NULL,
    [SHARED_RESID_AMOUNT] [DECIMAL](10, 2) NULL,
    [SHARED_RESID_PERCENT] [DECIMAL](10, 4) NULL,
    [SHARED_RESID_L_AND_D] [CHAR](1) NULL,
    [SHARED_RESID_COLLECTION_TYPE] [CHAR](1) NULL,
    [SHARED_RESID_MONTHS_OVERDUE] [SMALLINT] NULL,
    [ORIGINAL_LEASE_TERM] [SMALLINT] NULL,
    [ORIGINAL_LEASE_DATE] [DATETIME] NULL,
    [ORIGINAL_BASE_PAYMENT] [DECIMAL](10, 2) NULL,
    [ORIGINAL_MINIMUM_PAYMENTS] [DECIMAL](10, 2) NULL,
    [NEW_PAYMENT_PLAN_FLAG] [CHAR](1) NULL,
    [NEW_PAYMENT_PLAN_OFFSET] [SMALLINT] NULL,
    [NEW_PAYMENT_PLAN_DATE] [DATETIME] NULL,
    [NEW_MINIMUM_PAYMENTS] [DECIMAL](10, 2) NULL,
    [BILLING_PERIOD_NUMBER] [SMALLINT] NULL,
    [BILLING_PERIOD_1_INVOICES] [SMALLINT] NULL,
    [BILLING_PERIOD_1_PAYMENT] [DECIMAL](10, 2) NULL,
    [BILLING_PERIOD_2_INVOICES] [SMALLINT] NULL,
    [BILLING_PERIOD_2_PAYMENT] [DECIMAL](10, 2) NULL,
    [BILLING_PERIOD_3_INVOICES] [SMALLINT] NULL,
    [BILLING_PERIOD_3_PAYMENT] [DECIMAL](10, 2) NULL,
    [BILLING_PERIOD_4_INVOICES] [SMALLINT] NULL,
    [BILLING_PERIOD_4_PAYMENT] [DECIMAL](10, 2) NULL,
    [BILLING_PERIOD_5_INVOICES] [SMALLINT] NULL,
    [BILLING_PERIOD_5_PAYMENT] [DECIMAL](10, 2) NULL,
    [BILLING_PERIOD_6_INVOICES] [SMALLINT] NULL,
    [BILLING_PERIOD_6_PAYMENT] [DECIMAL](10, 2) NULL,
    [EQUIPMENT_AMOUNT] [DECIMAL](10, 2) NULL,
    [SERVICE_AMOUNT] [DECIMAL](10, 2) NULL,
    [MONTHS_OF_RECOURSE] [SMALLINT] NULL,
    [VENDOR_PAID_FLAG] [CHAR](1) NULL,
    [SALESPERSON_PAID_FLAG] [CHAR](1) NULL,
    [AP_ACCOUNT] [CHAR](5) NULL,
    [GL_AP_ACCOUNT] [CHAR](4) NULL,
    [GL_OWNER_COMPANY] [CHAR](4) NULL,
    [GL_BRANCH] [CHAR](1) NULL,
    [GL_DEPARTMENT] [CHAR](2) NULL,
    [GL_EQUIPMENT] [CHAR](2) NULL,
    [GL_STATE] [CHAR](2) NULL,
    [DEALER_RECOURSE_PERCENT] [DECIMAL](10, 4) NULL,
    [VENDOR_RECOURSE_PERCENT] [DECIMAL](10, 4) NULL,
    [SALESPERSON_RECOURSE_PERCENT] [DECIMAL](10, 4) NULL,
    [NUMBER_OF_UNITS] [SMALLINT] NULL,
    [INVOICES_SUBJECT_TO_DISCOUNT] [CHAR](1) NULL,
    [ORIGINAL_LEASE_PROGRAM] [CHAR](5) NULL,
    [MISSING_PAYMENT_COUNT] [SMALLINT] NULL,
    [BROKER_CODE] [CHAR](5) NULL,
    [REVENUE_SHARING_CODE] [CHAR](5) NULL,
    [REVENUE_SHARING_FACTOR] [DECIMAL](5, 2) NULL,
    [REVENUE_SHARING_FLAG] [CHAR](1) NULL,
    [DEALER_SHARING_CODE] [CHAR](5) NULL,
    [DEALER_SHARING_FACTOR] [DECIMAL](5, 2) NULL,
    [DEALER_SHARING_FLAG] [CHAR](1) NULL,
    [CHARGEBACK_RESERVE_FLAG] [CHAR](1) NULL,
    [FUNDING_FEE] [DECIMAL](10, 2) NULL,
    [FUNDING_FEE_INVOICED_FLAG] [CHAR](1) NULL,
    [LEASE_REFERENCE] [CHAR](30) NULL,
    [ORIGINAL_LEASE_NUMBER] [CHAR](12) NULL,
    [ORIGINAL_ACCOUNT_NUMBER] [CHAR](12) NULL,
    [BASE_PAYMENT_TAXABLE] [CHAR](1) NULL,
    [DAY_TO_CHARGE_BACK] [SMALLINT] NULL,
    [LESSEE_FED_ID_NUMBER] [CHAR](9) NULL,
    [ORIGINAL_PURCHASE_PRICE] [DECIMAL](10, 2) NULL,
    [ORIGINAL_PURCHASE_DATE] [DATETIME] NULL,
    [ACQUISITION_PURCHASE_PRICE] [DECIMAL](10, 2) NULL,
    [ACQUISITION_PURCHASE_DATE] [DATETIME] NULL,
    [BROKER_REV_SHAR_AMT_OVERRIDE] [DECIMAL](10, 2) NULL,
    [DEALER_REV_SHAR_AMT_OVERRIDE] [DECIMAL](10, 2) NULL,
    [UPFRONT_TAX_FLAG] [CHAR](1) NULL,
    [UPFRONT_TAX_AMOUNT] [DECIMAL](10, 2) NULL,
    [UPFRONT_TAX_BILLED] [CHAR](1) NULL,
    [SysStart] [DATETIME2](7) GENERATED ALWAYS AS ROW START NOT NULL,
    [SysEnd] [DATETIME2](7) GENERATED ALWAYS AS ROW END NOT NULL,
PRIMARY KEY CLUSTERED 
(
    [LEASE_NUMBER] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
    PERIOD FOR SYSTEM_TIME ([SysStart], [SysEnd])
) ON [PRIMARY]
WITH
(
SYSTEM_VERSIONING = ON ( HISTORY_TABLE = [dbo].[LEASES_HISTORY] )
)
GO

更新 2：

我无法提供真实数据，但这是我用来获取重复数据的查询。请注意，我是按表中的所有列分组的，所以这些是明确的重复项：

SELECT LEASE_NUMBER
     , SysStart
     , SysEnd
     , cnt
  FROM
       (   SELECT *
                , COUNT(*) cnt
             FROM dbo.LEASES_HISTORY AS l
            GROUP BY l.LEASE_NUMBER
                   , l.CREDIT_DECISION_CODE
                   , l.LEASE_APPLICATION
                   , l.ACCOUNT_NUMBER
                   , l.CELLULAR_NUMBER
                   , l.DEALER_CODE
                   , l.USERNAME
                   , l.LEASE_DATE
                   , l.NEW_USED_FLAG
                   , l.MANUFACTURER_CODE
                   , l.MODEL
                   , l.SERIAL_NUMBER_ELECTRONIC
                   , l.SERIAL_NUMBER_MECHANICAL
                   , l.CONTROL_HEAD
                   , l.LEASE_TERM
                   , l.LESSEE_CITY
                   , l.LESSEE_ADDRESS_1
                   , l.LESSEE_ADDRESS_2
                   , l.LESSEE_STATE
                   , l.LESSEE_ZIP_CODE
                   , l.LESSEE_NAME
                   , l.KEY_NAME
                   , l.BASE_PAYMENT
                   , l.MONTHLY_SALES_TAX
                   , l.INSURANCE
                   , l.MONTHLY_PAYMENT
                   , l.SECURITY_DEPOSIT
                   , l.INVOICES_GENERATED_COUNT
                   , l.DATE_LAST_INVOICED
                   , l.DATE_LAST_LATE_FEE
                   , l.SECURITY_DEPOSITS_INVOICED
                   , l.SECURITY_DEPOSITS_REFUNDED
                   , l.ADVANCE_RENT
                   , l.ADVANCE_SALES_TAX
                   , l.TOTAL_ADVANCE_PAYMENT
                   , l.AUTO_LEASE_EXPIRATION_DATE
                   , l.PAYMENTS_REMAINING
                   , l.PV_PAYMENTS_REMAINING
                   , l.TAX_RATE
                   , l.TAX_STATE
                   , l.LEASE_FACTOR
                   , l.AMOUNT_FINANCED
                   , l.REMARKS
                   , l.VOUCHER_NUMBER
                   , l.BILL_METHOD_ADVANCE
                   , l.FINANCING_PACKAGE
                   , l.BUYOUT_AMOUNT
                   , l.BUYOUT_DATE
                   , l.DEPRECIATION_MONTHS
                   , l.SALVAGE_VALUE
                   , l.LAST_DEPRECIATION_DATE
                   , l.LAST_DEPRECIATION_AMOUNT
                   , l.ACCUMULATED_DEPRECIATION
                   , l.BILL_METHOD_BUYOUT
                   , l.BUYOUT_INVOICED
                   , l.RECEIVED_DATE
                   , l.LEASE_PROGRAM
                   , l.PAYMENTS_INCLUDED_ADVANCE
                   , l.SALESPERSON_CODE
                   , l.UNGUARANTEED_RESIDUAL_VALUE
                   , l.UNEARNED_INCOME
                   , l.DIRECT_COST
                   , l.AMORTIZABLE_UNEARNED_INCOME
                   , l.AMORTIZED_FLAG
                   , l.RESIDUAL_VALUE_PERCENTAGE
                   , l.MINIMUM_LEASE_PAYMENTS
                   , l.IMPLICIT_MONTHLY_INTEREST_RATE
                   , l.AP_POSTED_FLAG
                   , l.AP_POSTED_DATE
                   , l.CAPITALIZED_LEASE_FLAG
                   , l.LEASE_STATUS
                   , l.GROSS_INVESTMENT
                   , l.ADVANCE_BILLED_FLAG
                   , l.AP_VOUCHER_NUMBER
                   , l.BANK_PACKAGE
                   , l.INSURANCE_BINDER
                   , l.CURRENT_BUYOUT
                   , l.LEASE_AGE_YEARS
                   , l.GUARANTOR_NAME
                   , l.GUARANTOR_ADDRESS_LINE_1
                   , l.GUARANTOR_ADDRESS_LINE_2
                   , l.GUARANTOR_CITY
                   , l.GUARANTOR_STATE
                   , l.GUARANTOR_ZIP
                   , l.GUARANTOR_TELEPHONE
                   , l.GUARANTOR_SS_NUMBER
                   , l.GUARANTOR
                   , l.BILL_CYCLES_DEFER
                   , l.REVENUE_ACCOUNT
                   , l.INVOICE_TYPE
                   , l.CORRESPONDENCE_FLAG
                   , l.DOWN_PAYMENT
                   , l.ADVANCE_INSURANCE
                   , l.ORIGINAL_EQUIPMENT_COST
                   , l.SERVICING_DEALER_CODE
                   , l.DEALER_BUYOUT_DATE
                   , l.LEASE_OWNER_CODE
                   , l.LEASE_OWNER_DATE
                   , l.VENDOR_CODE
                   , l.SPLIT_FUNDING_COUNT
                   , l.DEALER_AMOUNT
                   , l.VENDOR_AMOUNT
                   , l.SALESPERSON_AMOUNT
                   , l.DEALER_OFFICE
                   , l.ASSESSMENT_YEAR
                   , l.PROPERTY_TAX_RATE
                   , l.ASSESSMENT_FACTOR
                   , l.MONTHLY_PROPERTY_TAX
                   , l.MANAGER_CODE
                   , l.DEALER_BUYOUT_PROGRAM
                   , l.SHARED_RESID_METHOD
                   , l.SHARED_RESID_AMOUNT
                   , l.SHARED_RESID_PERCENT
                   , l.SHARED_RESID_L_AND_D
                   , l.SHARED_RESID_COLLECTION_TYPE
                   , l.SHARED_RESID_MONTHS_OVERDUE
                   , l.ORIGINAL_LEASE_TERM
                   , l.ORIGINAL_LEASE_DATE
                   , l.ORIGINAL_BASE_PAYMENT
                   , l.ORIGINAL_MINIMUM_PAYMENTS
                   , l.NEW_PAYMENT_PLAN_FLAG
                   , l.NEW_PAYMENT_PLAN_OFFSET
                   , l.NEW_PAYMENT_PLAN_DATE
                   , l.NEW_MINIMUM_PAYMENTS
                   , l.BILLING_PERIOD_NUMBER
                   , l.BILLING_PERIOD_1_INVOICES
                   , l.BILLING_PERIOD_1_PAYMENT
                   , l.BILLING_PERIOD_2_INVOICES
                   , l.BILLING_PERIOD_2_PAYMENT
                   , l.BILLING_PERIOD_3_INVOICES
                   , l.BILLING_PERIOD_3_PAYMENT
                   , l.BILLING_PERIOD_4_INVOICES
                   , l.BILLING_PERIOD_4_PAYMENT
                   , l.BILLING_PERIOD_5_INVOICES
                   , l.BILLING_PERIOD_5_PAYMENT
                   , l.BILLING_PERIOD_6_INVOICES
                   , l.BILLING_PERIOD_6_PAYMENT
                   , l.EQUIPMENT_AMOUNT
                   , l.SERVICE_AMOUNT
                   , l.MONTHS_OF_RECOURSE
                   , l.VENDOR_PAID_FLAG
                   , l.SALESPERSON_PAID_FLAG
                   , l.AP_ACCOUNT
                   , l.GL_AP_ACCOUNT
                   , l.GL_OWNER_COMPANY
                   , l.GL_BRANCH
                   , l.GL_DEPARTMENT
                   , l.GL_EQUIPMENT
                   , l.GL_STATE
                   , l.DEALER_RECOURSE_PERCENT
                   , l.VENDOR_RECOURSE_PERCENT
                   , l.SALESPERSON_RECOURSE_PERCENT
                   , l.NUMBER_OF_UNITS
                   , l.INVOICES_SUBJECT_TO_DISCOUNT
                   , l.ORIGINAL_LEASE_PROGRAM
                   , l.MISSING_PAYMENT_COUNT
                   , l.BROKER_CODE
                   , l.REVENUE_SHARING_CODE
                   , l.REVENUE_SHARING_FACTOR
                   , l.REVENUE_SHARING_FLAG
                   , l.DEALER_SHARING_CODE
                   , l.DEALER_SHARING_FACTOR
                   , l.DEALER_SHARING_FLAG
                   , l.CHARGEBACK_RESERVE_FLAG
                   , l.FUNDING_FEE
                   , l.FUNDING_FEE_INVOICED_FLAG
                   , l.LEASE_REFERENCE
                   , l.ORIGINAL_LEASE_NUMBER
                   , l.ORIGINAL_ACCOUNT_NUMBER
                   , l.BASE_PAYMENT_TAXABLE
                   , l.DAY_TO_CHARGE_BACK
                   , l.LESSEE_FED_ID_NUMBER
                   , l.ORIGINAL_PURCHASE_PRICE
                   , l.ORIGINAL_PURCHASE_DATE
                   , l.ACQUISITION_PURCHASE_PRICE
                   , l.ACQUISITION_PURCHASE_DATE
                   , l.BROKER_REV_SHAR_AMT_OVERRIDE
                   , l.DEALER_REV_SHAR_AMT_OVERRIDE
                   , l.UPFRONT_TAX_FLAG
                   , l.UPFRONT_TAX_AMOUNT
                   , l.UPFRONT_TAX_BILLED
                   , l.SysStart
                   , l.SysEnd
           HAVING COUNT(*) > 1
       ) a;

在此处输入图像描述

更新 3：好的，此时这是我能够获得的新信息。我们试图捕捉rpc_completed事件以了解实际发生的情况。跟踪文件有 7 个不同的语句，event_sequence编号不同。据我了解，这意味着这些语句是在不同的事务中执行的。稍后我将尝试准备更详细的更新，但现在语句如下（除了最后一个语句之外的所有语句都是使用sp_prepexec存储过程执行的）：

该行实际上有 3 种不同的状态，我们称它们为x,y,z

  • 带有状态的 PK 更新记录x——此时数据库中没有这样的记录
  • 带有状态的 PK 更新记录y——此时数据库中没有这样的记录
  • 插入带x状态的记录
  • INSERT 带有y状态的记录——这因违反 PK 约束而失败
  • 更新记录到x状态——实际上没有改变任何行，所以实际记录没有改变
  • 将记录更新到y状态——实际记录已更改
  • UPDATE 使用过程记录到z状态sp_execute，其中 handle_id 与上一次更新（更新到z状态）相同，但通过参数传递的值不同

所以在这些操作结束时，我们有：

原始表处于z状态，历史表有类似的东西（日期时间是真实值）：

  • x状态栏，2017-11-01 16:55:31.3358248, 2017-11-01 16:55:31.3358248
  • x状态栏，2017-11-01 16:55:31.3358248, 2017-11-01 16:55:31.3358248
  • y状态栏，2017-11-01 16:55:31.3358248, 2017-11-01 16:55:41.9296659
4

2 回答 2

4

临时表使用事务的开始时间作为使用的时间戳（请参阅MS Docs中插入、更新和删除部分下的临时表）。通过在您的事务中进行多次更新，或者在同一事务中进行插入后更新，您将获得具有相同开始/结束时间的给定主键值的多条记录。

链接摘录：

UPDATES：在 UPDATE 时，系统将行的先前值存储在历史表中，并根据系统时钟将 SysEndTime 列的值设置为当前事务的开始时间（在 UTC 时区）

这是一个将重现该行为的示例。ProductsHistory请注意，表中的 Miniature Widgets 有 2 个相同的条目ProductId = 2。另请注意，尽管更新ProductId = 1没有更改值，但它们仍然创建了相同的历史表记录。

create table test.Products (
        ProductId       int not null primary key,
        ProductName     nvarchar(100) not null,
        EffectiveDate   datetime2(7) generated always as row start hidden not null,
        EndingDate      datetime2(7) generated always as row end hidden not null,
        period for system_time (EffectiveDate, EndingDate)
        )
        with (system_versioning = on (history_table = test.ProductsHistory));

go

begin tran

insert  test.Products (ProductId, ProductName) values
        (1, N'Widgets'),
        (2, N'Miniature Widgets');

update  test.Products set ProductName = 'Tiny Widgets' where ProductId = 2;
update  test.Products set ProductName = 'Miniature Widgets' where ProductId = 2;
update  test.Products set ProductName = 'Tiny Widgets' where ProductId = 2;
update  test.Products set ProductName = 'Widgets' where ProductId = 1;
update  test.Products set ProductName = 'Widgets' where ProductId = 1;

commit tran

select  p.ProductId, p.ProductName, p.EffectiveDate, p.EndingDate
from    test.Products for system_time all p;

select  *
from    test.ProductsHistory;
于 2017-10-31T12:44:55.097 回答
0

I'm going to add another possibility as a separate answer although I think this is far less likely - the server clock has changed. I have seen instances (more with text log files than SQL but still possible) with time overlap where the server/PC time has changed. This can happen when daylight savings starts/ends (although in this scenario it is unlikely since the start/end fields are in UTC). A more remote possibility is that you are having server clock drift. I doubt you would see this on a server - we were seeing it on single core industrial PCs running hot and CPU frequently maxxed out. Even synching the clock daily we could be short by a minute or 2 at the end of the day.

于 2017-11-01T15:51:06.383 回答