SQL query alternative for performance improval

  • I have a query where i am suing inline query which will take the latest data from table

    " select username from table where conditions>22 order by column1 desc"

    i am using like this :

    select distinct col1,col2,(select top 1 username from table where conditions>22 order by column1 desc) as col3,

    (select top 1 names from table where conditions>22 order by column1 desc) as col4.... from table1

    UNION

    select col1,col2,(select top 1 username from table where conditions>22 order by column1 desc) as col3,

    (select top 1 names from table where conditions>22 order by column1 desc) as col4.... from table2

    because of the above query I am getting the result very slow, it take lot of time to get result.

    Will joins work? if yes then how can i use in place of inline queries since inline queries give me top 1 latest data because of

    order by desc use.

    I want some alternative to this inline queries.

  • Please post table def and sample data in a ready to use format as described in the first link in my signature.

    Also, please include your expected result based on the sample data.



    Lutz
    A pessimist is an optimist with experience.

    How to get fast answers to your question[/url]
    How to post performance related questions[/url]
    Links for Tally Table [/url] , Cross Tabs [/url] and Dynamic Cross Tabs [/url], Delimited Split Function[/url]

  • Check the attached txt file for design and query to be edited.

  • Please include sample data and expected/desired results too.

    The absence of evidence is not evidence of absence.
    Martin Rees

    You can lead a horse to water, but a pencil must be lead.
    Stan Laurel

  • What is the business logic behind it?

    All of the subqueries use a TOP 1 without an ORDER BY. What's the purpose?

    Why not simply using the following approach (example of one part of the UNION statement):

    SELECT

    [Credit Note NO],

    [Department],

    MIN([Designation]) AS [Pending WITH Designation],

    MIN([UserName]) AS [Pending WITH],

    DATEDIFF(DD, MAX([Modified]), GETDATE()) AS [Bucket]

    FROM dbo.App1

    WHERE [Status] = 'Pending'

    GROUP BY [Credit Note NO],[Department]

    You might also want to verify if UNION is really needed and you cannot use UNION ALL.



    Lutz
    A pessimist is an optimist with experience.

    How to get fast answers to your question[/url]
    How to post performance related questions[/url]
    Links for Tally Table [/url] , Cross Tabs [/url] and Dynamic Cross Tabs [/url], Delimited Split Function[/url]

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