How to use OFFSET and Fetch without Order by in SQL Server

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我寻月下人不归
我寻月下人不归 2021-02-07 13:35

I want use OFFSET and Fetch in my SQL server 2012 query.But without any order by.I can not use order by.Because my sort order will be lost. How can I use OFFSET and Fetch withou

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  • 2021-02-07 13:43

    Offset/Fetch requires an order by clause. You can use the CURRENT_TIMESTAMP to bypass this requirement if you don't want to go by any order. I am not sure but, this should return rows based on the order of storage (clustered index maybe)

    So changing your code to this should solve the issue -

    INSERT INTO @TempTable [some columns]  
    select [some columns] from table1 order by col1 
    INSERT INTO @TempTable [same columns]
    select [some columns] from table2 order by col2
    select * from @TempTable **order by current_timestamp** OFFSET 20 ROWS FETCH NEXT 50 ROWS ONLY
    
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  • 2021-02-07 13:53

    By adding an identity column to the temp table variable

        declare @TempTable table([some columns], rownr int identity(1,1) )
    
        INSERT INTO @TempTable [some columns]  
        select [some columns] from table1  order by col1 
    
        INSERT INTO @TempTable [same columns]
        select [some columns] from table2 order by col2
    

    An automatic incrementing number is added for each row, in the order in which they are added to the temp table. The inserts don't need to fill this column, so the inserts can remain as they are. The identity column can then be used for the order by:

     select * from @TempTable Order by rownr OFFSET 20 ROWS FETCH NEXT 50 ROWS ONLY
    
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  • 2021-02-07 13:55

    You cannot avoid using the required syntax of a ORDER BY with OFFSET and FETCH.

    It is however possible to disassociate the ORDER BY clause that you must provide in order to perform paging from the natural table order created by the record insert process.

    Using the solution below you do not have to make any changes to the underlying table either

    Select 0 as TempSort, T.* From MyTable T ORDER BY TempSort OFFSET 2 ROWS FETCH NEXT 3 ROWS
    
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  • 2021-02-07 13:56

    There is an even simpler way of providing a dummy ORDER BY clause:

    select * from @TempTable ORDER BY(SELECT NULL) OFFSET 20 ROWS FETCH NEXT 50 ROWS ONLY
    
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  • 2021-02-07 14:06

    After research and according to comments, The clear and summary answer is : "There is no way!"

    But you can remain your sort order with row_number(). So I provided a new tested query that remain the sort order of temp table(final table) with OFFSET and FETCH clause.

        INSERT INTO @TempTable [some columns]  
        select [some columns],row_number() OVER (order by col1) row from table1 order by col1 
    
        declare @maxrow int
        select @maxrow=max(rn) from @TempTable
    
        INSERT INTO @TempTable [same columns]
        select [some columns],((row_number() OVER (order by col2)) + @maxrow) row from table2 order by col2
    
        select * from @TempTable Order by row  OFFSET 20 ROWS FETCH NEXT 50 ROWS ONLY
    
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