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Insert random values

  • June 28, 2010 at 1:52 am

    #220545

    Dear Friends,

    I am wondering if you could give me a hand in this situation.

    I am a new user for sql and i am currently work in task that requires me to update random values to my table. I have 1000 rows consist of 0 and 1 values and i would like to randomly change 100 cells that contain 0 values to 1. I would like to know which sql statement can help me to perform this.

    Thank you for your assistant in advance.

    Regards,

    🙂

  • June 28, 2010 at 1:57 am

    #1185566

    Hi ,

    The consensus of opinion is that newid() provides a pretty good randomness factor.

    So if you select top(100) * from <yourtable> order by newid() , you will get 100 random rows.

    If the table has a PK , which i should , you can directly update from that list or wrap that in a CTE and update using that.


    Clear Sky SQL
    My Blog[/url]

  • June 28, 2010 at 7:25 am

    #1185720

    Hi Dave Ballantyne

    Thank you for your answer but i would like know that CTE can be used to update random columns. because when i execute the following statement, i get 100 rows in random. Can i use CTE to update 100 fields in different columns. For example column, i update 10 fields and in column two i update 25 and so on till 100 fields have been changed.

    select top 100 from

    Table_A

    order by newid ()

    Thanks a lot

    🙁

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