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Editorial Team
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Asked: 2026-05-30T06:56:40+00:00

Say for example, one has a table with certain rows, how does one prevent

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Say for example, one has a table with certain rows, how does one prevent updates to certain rows based on a condition equalling true but allow the update to commit on all rows where the condition is false.

take this example where I “lock” all rows prior to 1/4/2007 by aborting the whole transaction

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
CREATE TABLE [dbo].[tbl_TriggerTest] (
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [Value] [varchar](25) NULL,
    [Date] [datetime] NULL,
 CONSTRAINT [PK_tbl_TriggerTest] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

GO
SET ANSI_PADDING OFF
GO
SET IDENTITY_INSERT [dbo].[tbl_TriggerTest] ON 

GO
INSERT [dbo].[tbl_TriggerTest] ([ID], [Value], [Date]) VALUES (1, N'12', CAST(0x0000979A00000000 AS DateTime))
GO
INSERT [dbo].[tbl_TriggerTest] ([ID], [Value], [Date]) VALUES (2, N'13', CAST(0x00009A7500000000 AS DateTime))
GO
INSERT [dbo].[tbl_TriggerTest] ([ID], [Value], [Date]) VALUES (3, N'14', CAST(0x00009BE200000000 AS DateTime))
GO
INSERT [dbo].[tbl_TriggerTest] ([ID], [Value], [Date]) VALUES (4, N'4', CAST(0x00009D4F00000000 AS DateTime))
GO
SET IDENTITY_INSERT [dbo].[tbl_TriggerTest] OFF
GO
CREATE TRIGGER [dbo].[LockOldWelshRows] ON [dbo].[tbl_TriggerTest]
    FOR UPDATE
AS
    BEGIN
        DECLARE @Count INT
        SELECT  @Count = COUNT([ID])
        FROM    INSERTED
        WHERE   [Date] < CONVERT(DATETIME, '01/04/2007 00:00:00', 103)

        IF @Count > 0 
            BEGIN
                RAISERROR('Rows prior to 01/04/2007 are locked',16,1) 
                ROLLBACK TRANSACTION
                RETURN ;
            END
    END

GO

If one was to run the following:

UPDATE [tbl_TriggerTest] SET [Value] = [Value] + 'M'

The transaction would fail with error:

Msg 50000, Level 16, State 1, Procedure LockOldWelshRows, Line 12
Rows prior to 01/04/2007 are locked
Msg 3609, Level 16, State 1, Line 1
The transaction ended in the trigger. The batch has been aborted.

Is there a way of modifying this trigger to allow the transaction to commit, but only rows where the date is > 1/4/2007

This is a VERY brief example (the tables i am working with are far more complex), and if i am honest, i think it’s cleaner if the whole transaction fails, i was just curious as to how it could be done.

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1 Answer

  1. Editorial Team

    You’d need a BEFORE aka INSTEAD OF trigger and filter to allowed rows only.

    Untested:

    CREATE TRIGGER [dbo].[LockOldWelshRows] ON [dbo].[tbl_TriggerTest]
    INSTEAD OF UPDATE
AS
    BEGIN

      UPDATE 
         T
      SET 
         T.SomeCol = I.SomeCol...
      FROM
         [dbo].[tbl_TriggerTest] T
         JOIN 
         INSERTED I ON T.keycol = I.keycol 
      WHERE
         T.[Date] >= '20070401';

    END

GO
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