Understanding and Using APPLY (Part 2)

  • Paul White

    SSC Guru

    Points: 150442

    Comments posted to this topic are about the item Understanding and Using APPLY (Part 2)

  • Paul White

    SSC Guru

    Points: 150442

    I would like to express my sincere thanks to the following people, for their help in producing this article:

    Amanda Lawrence

    Jeff Moden MVP

    Chris Morris

    Lutz Müller

    Jason Brimhall[/url]

    Paul

  • peter-757102

    SSCertifiable

    Points: 6877

    Excellent and with enough extra material to make it interesting for those already familiar with apply!

  • clementhuge

    SSC-Addicted

    Points: 445

    Very interesting. I alrady use cross apply (mostly with table-valued functions) and I use a lot of xqueries. I like the last t-sql code about xquery. I was not using aliases and also navigating with rowset and the apply functions. Good tip!

    Clement

  • Mike M - DBA2B

    Right there with Babe

    Points: 764

    Thank you once again, Paul. I'll be experimenting today.

    I just noticed something that I think is in error:

    The first CROSS JOIN example under your "Equivalent Expressions Using APPLY and JOIN" header performs "ORDER BY S.name ASC, S.name ASC". Is that supposed to be "S.name ASC, J.name ASC"?

    Regards,

    Mike M

  • greenclay

    SSC Enthusiast

    Points: 109

    Thanks for this article. There's a lot to consider here.

    In the CROSS JOIN section, the query

    [font="Courier New"]SELECT S.name, J.name

    FROM dbo.Student S

    CROSS

    JOIN dbo.Subject J

    ORDER BY S.name ASC, S.name ASC;

    [/font]

    should read

    [font="Courier New"]SELECT S.name, J.name

    FROM dbo.Student S

    CROSS

    JOIN dbo.Subject J

    ORDER BY S.name ASC, J.name ASC;[/font]

    should it not?

  • Daniel Bowlin

    SSC-Dedicated

    Points: 34566

    A thorough and well explained article. The supplemental file was a real bonus. Thanks.

  • WayneS

    SSC Guru

    Points: 95341

    Paul - another excellent article on using APPLY. Thank you so much for doing this... now I need to find the time to disect these two articles, and get a good understanding of them.

    Again, thanks for doing these.

    Wayne
    Microsoft Certified Master: SQL Server 2008
    Author - SQL Server T-SQL Recipes


    If you can't explain to another person how the code that you're copying from the internet works, then DON'T USE IT on a production system! After all, you will be the one supporting it!
    Links:
    For better assistance in answering your questions
    Performance Problems
    Common date/time routines
    Understanding and Using APPLY Part 1 & Part 2

  • Trey Staker

    SSCarpal Tunnel

    Points: 4736

    Very well written article. Thanks Paul.

    ---------------------------------------------------------------------
    Use Full Links:
    KB Article from Microsoft on how to ask a question on a Forum

  • Tom Garth

    SSCertifiable

    Points: 6173

    I will be using APPLY beginning this week. Thanks for a really understandable series.

    Tom Garth
    Vertical Solutions[/url]

    "There are three kinds of men. The one that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves." -- Will Rogers
  • ckuroda

    SSC-Addicted

    Points: 461

    This is an excellent follow up to the first article. In the example for displaying a comma separated values list of all the test scores for each student, could you have also used the coalesce function to prevent the first comma in the output?

  • SQLRNNR

    SSC Guru

    Points: 281210

    Paul White NZ (4/18/2010)


    I would like to express my sincere thanks to the following people, for their help in producing this article:

    Amanda Lawrence

    Jeff Moden MVP

    Chris Morris

    Lutz Müller

    Jason Brimhall[/url]

    Paul

    You're welcome.

    It is a good article - and it was a pleasure to help.

    Jason...AKA CirqueDeSQLeil
    _______________________________________________
    I have given a name to my pain...MCM SQL Server, MVP
    SQL RNNR
    Posting Performance Based Questions - Gail Shaw[/url]
    Learn Extended Events

  • Steve Jones - SSC Editor

    SSC Guru

    Points: 715841

    Excellent job, Paul. It helped me learn a few things about a command I rarely use.

  • LutzM

    SSC Guru

    Points: 107049

    Great article series, Paul!

    It was a pleasure being selected to get a preview and to give some thoughts/comments.

    Let's see how long it takes until I have referenced those two articles more often then I did Jeffs CrossTab/DynamicCrossTab 😀



    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]

  • UMG Developer

    SSChampion

    Points: 13482

    Paul, Wow, thanks for these two articles they really helped me understand better use of APPLY. Now if I can just remember all of that I think I will use it a lot more.

    Thanks again!

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