Union Forcing Distinct

• cmerrell

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  May 13, 2013 at 11:22 pm

  #272674

  Comments posted to this topic are about the item Union Forcing Distinct

• David McKinney

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  May 14, 2013 at 4:14 am

  #1614912

  Not an issue for me...this has always been the behaviour of UNION.

  I've often used

  select c,b FROM #a

  UNION

  select c,b FROM #a

  to eliminate / identify duplicates.

  As for multiple UNIONs / UNION ALLs it just applies them sequentially.

• SQLHeap

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  May 14, 2013 at 7:43 am

  #1614994

  varchar(1)?

  There is an exception to every rule, except this one...

• David In BC

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  May 14, 2013 at 10:02 am

  #1615086

  Interesting - I wouldn't have suspected that UNION makes the result set from each separate select "distinct".

  I would guess that a "UNION" is really a "UNION ALL", with a subsequent "SELECT DISTINCT" to return the rows to the user.

• akljfhnlaflkj

  SSC Guru

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  May 2, 2016 at 1:14 pm

  #1876024

  Thanks for the script.