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Editorial Team
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Asked: 2026-06-09T16:48:55+00:00

I have seen a question on here about this however it was old so

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I have seen a question on here about this however it was old so I will ask again in case a solution now exists.

My issue is this. I have a database table which I wish to select from but I want to lock the rows that I have selected. The reason for this is that I may have another process running that will also want to select the same rows and I want to prevent this.

Imagine I have two processes doing the same thing. One performs a select and begins to perform its processing of the data. Then a few seconds later the next process comes along and does a select but because the rows aren’t locked it also takes the same records and begins to process them. This is of course a bad situation to be in. In Oracle you can use SELECT FOR UPDATE which will take out a lock on the rows to prevent them from being used by the 2nd process. How can this be achieved in SQL Server 2008?

I should add that I can only use standard sql statements. I do not have access to procedures, functions etc. It has to be done via a simple statement. Its a long story and a design consideration that has been taken out of my hands. The solution must be able to be stored in a table, retrieved later and then run via the ADO objects in C# in particular assigned to a command object.

How can a lock be applied to this statement?

SELECT * 
FROM 
  (SELECT TOP (20) * 
   FROM [TMA_NOT_TO_ENTITY_QUEUE]  
   WHERE [TMA_NOT_TO_ENTITY_QUEUE].[STATE_ID] = 2 
   ORDER BY TMA_NOT_TO_ENTITY_QUEUE.ID) a
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1 Answer

  1. Editorial Team

    You need to use one of the so-called table hints:

    The update lock prevents other processes from attempting to update or delete the rows in question – but it does not prevent read access:

        SELECT TOP (20) * 
    FROM [TMA_NOT_TO_ENTITY_QUEUE] WITH (UPDLOCK)
    WHERE [TMA_NOT_TO_ENTITY_QUEUE].[STATE_ID] = 2 
    ORDER BY TMA_NOT_TO_ENTITY_QUEUE.ID

    There’s also an exclusive lock, but basically, the update lock should be enough. Once you’ve selected your rows with an update lock, those rows are “protected” against updates and writes until your transaction ends.

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