Need to optimize/Rewrite this query..

• Chinna

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  July 5, 2013 at 12:21 am

  #274932

  Implement a function with below logic in an efficient way ...Pass @var1 and return @var2 ...How can it be done as it does table scan now ??

  DECLARE @Var1 VARCHAR(10)

  DECLARE @Var2 VARCHAR(100)

  SELECT @var2= var2 FROM #test

  WHERE var1 = @Var1

  Thanks in advance

  Thanks,
  Chinna

  Its the Journey which gives you Happiness not the Destination-- Dan Millman

• Phil Parkin

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  July 5, 2013 at 12:25 am

  #1629945

  Sri8143 (7/5/2013)

  ---

  Implement a function with below logic in an efficient way ...Pass @var1 and return @var2 ...How can it be done as it does table scan now ??

  DECLARE @Var1 VARCHAR(10)

  DECLARE @Var2 VARCHAR(100)

  SELECT @var2= var2 FROM #test

  WHERE var1 = @Var1

  Thanks in advance

  Try creating an index on your temp table before running that query - something like this:

  create nonclustered index ix_test_var1 on #test(var1) include(var2)

  ---

• ChrisM@Work

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  Points: 186127

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  July 5, 2013 at 1:27 am

  #1629963

  ALTER FUNCTION [dbo].[IF_GetVar2]

  (@Var1 VARCHAR(10))

  RETURNS TABLE WITH SCHEMABINDING AS

  RETURN

  SELECT var2

  FROM test

  WHERE var1 = @Var1

  ;

  GO

  -- Testing:

  SELECT var2 FROM IF_GetVar2('Somevalue')

  -- Examine the execution plan and create a new index

  -- on table 'test' to support seeks if necessary - as in Phil's post.

  ^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

  For fast, accurate and documented assistance in answering your questions, please read this article.
  Understanding and using APPLY, (I) and (II) Paul White
  Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden

• Chinna

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  Points: 5408

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  July 5, 2013 at 1:42 am

  #1629972

  Thanks Guys for the response.. But just want to know if there is a workaround for this issue using crossapply ?

  AS it is looping through all the records now ..

  Thanks,
  Chinna

  Its the Journey which gives you Happiness not the Destination-- Dan Millman

• ChrisM@Work

  SSC Guru

  Points: 186127

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  July 5, 2013 at 1:53 am

  #1629975

  What do you mean by 'looping'? A table or clustered index scan? You can incorporate an iTVF into a query using APPLY but that won't help at all if there isn't a supporting index for the query.

  ^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

  For fast, accurate and documented assistance in answering your questions, please read this article.
  Understanding and using APPLY, (I) and (II) Paul White
  Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden