Multiple Column Joins

• chcampbelljr 84439

  Mr or Mrs. 500

  Points: 518

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  November 6, 2013 at 12:44 pm

  #300021

  I have two tables and I need to join on one column if there is a match else join on another

  Example

  SELECT

  tb1.Col1

  , tb2.Col2

  , tb2.Col3

  FROM TB1

  LEFT OUTER JOIN TB2

  ON tb1.Col1 = tb2.Col1

  OR tb1.Col2 = tb2.Col2

  Problem is, using OR the performance is horrible, what is a more efficient way of doing this?

• Keith Tate

  SSCrazy Eights

  Points: 9938

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  November 6, 2013 at 12:48 pm

  #1664547

  you could use a union to do the same thing:

  select tb1.Col1, tb2.Col2, tb2.Col3

  from TB1

  left outer join TB2 on tb2.Col1 = tb2.Col1

  union

  select tb1.Col1, tb2.Col2, tb2.Col3

  from TB1

  left outer join TB2 on tb2.Col2 = tb2.Col2

  ---

  
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• chcampbelljr 84439

  Mr or Mrs. 500

  Points: 518

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  November 6, 2013 at 1:26 pm

  #1664556

  That is perfect!! Before, the query that I was running took over 6 minutes to run. This one ran seconds. Thank you very much!!!