Insert random values

• n_a_h_k

  Valued Member

  Points: 74

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  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,

  

• Dave Ballantyne

  SSC-Dedicated

  Points: 33667

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  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]

• n_a_h_k

  Valued Member

  Points: 74

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  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