Click here to monitor SSC
SQLServerCentral is supported by Redgate
 
Log in  ::  Register  ::  Not logged in
 
 
 


SQL Server Ranking Functions


SQL Server Ranking Functions

Author
Message
WayneS
WayneS
SSCertifiable
SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)

Group: General Forum Members
Points: 6230 Visits: 10398
Comments posted to this topic are about the item SQL Server Ranking Functions

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, How to ask a question, Performance Problems, Common date/time routines,
CROSS-TABS and PIVOT tables Part 1 & Part 2, Using APPLY Part 1 & Part 2, Splitting Delimited Strings

Jeff Moden
Jeff Moden
SSC-Forever
SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)

Group: General Forum Members
Points: 44974 Visits: 39866
Yowch... the formatting monster hit the code hard on this one. I hope Steve can fix it soon.

Glad to see you in the saddle again, Wayne. It's too late for me to read through it tonight but you can bet I'll read it in the morning over coffee.

--Jeff Moden

RBAR is pronounced ree-bar and is a Modenism for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
     Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column.
Although they tell us that they want it real bad, our primary goal is to ensure that we dont actually give it to them that way.
Although change is inevitable, change for the better is usually not.
Just because you can do something in PowerShell, doesnt mean you should. Wink

Helpful Links:
How to post code problems
How to post performance problems
Forum FAQs
SQLRNNR
SQLRNNR
SSC-Insane
SSC-Insane (21K reputation)SSC-Insane (21K reputation)SSC-Insane (21K reputation)SSC-Insane (21K reputation)SSC-Insane (21K reputation)SSC-Insane (21K reputation)SSC-Insane (21K reputation)SSC-Insane (21K reputation)

Group: General Forum Members
Points: 21071 Visits: 18259
Congrats on getting this article out Wayne.



Jason AKA CirqueDeSQLeil
I have given a name to my pain...
MCM SQL Server, MVP


SQL RNNR

Posting Performance Based Questions - Gail Shaw

Michael Meierruth
Michael Meierruth
SSChasing Mays
SSChasing Mays (647 reputation)SSChasing Mays (647 reputation)SSChasing Mays (647 reputation)SSChasing Mays (647 reputation)SSChasing Mays (647 reputation)SSChasing Mays (647 reputation)SSChasing Mays (647 reputation)SSChasing Mays (647 reputation)

Group: General Forum Members
Points: 647 Visits: 2507
Wayne,
You state what I always wanted to hear stated, i.e. that ROW_NUMBER()'s ORDER BY is not the same as the SELECT's ORDER BY. Yet, always - haven't encountered an exception yet, when you perform a SELECT the output is always in the order specified by ROW_NUMBER()'s ORDER BY without the presence of an ORDER BY in the SELECT.
How do you explain that?

Oh yes, those ORDERBY and PARTITIONBY need fixing.Hehe
mister.magoo
mister.magoo
SSCrazy
SSCrazy (2.3K reputation)SSCrazy (2.3K reputation)SSCrazy (2.3K reputation)SSCrazy (2.3K reputation)SSCrazy (2.3K reputation)SSCrazy (2.3K reputation)SSCrazy (2.3K reputation)SSCrazy (2.3K reputation)

Group: General Forum Members
Points: 2266 Visits: 7821
Michael Meierruth (4/20/2010)
Wayne,
You state what I always wanted to hear stated, i.e. that ROW_NUMBER()'s ORDER BY is not the same as the SELECT's ORDER BY. Yet, always - haven't encountered an exception yet, when you perform a SELECT the output is always in the order specified by ROW_NUMBER()'s ORDER BY without the presence of an ORDER BY in the SELECT.
How do you explain that?

Oh yes, those ORDERBY and PARTITIONBY need fixing.Hehe


You just have to look at the execution plan to see why they come out in that order without a specific order by on the select.

You will see a SORT to get the row numbers in the correct sequence. In the absence of any ORDER BY clause, there is no reason for the result set to be sorted again.

MM


select geometry::STGeomFromWKB(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




  • Forum Etiquette: How to post Reporting Services problems
  • Forum Etiquette: How to post data/code on a forum to get the best help - by Jeff Moden
  • How to Post Performance Problems - by Gail Shaw

  • SW_Lindsay
    SW_Lindsay
    SSC-Enthusiastic
    SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)

    Group: General Forum Members
    Points: 121 Visits: 309
    Nice and helpful article - Thanks. Just Curious...

    To select eligible candidates in the first select you say

    select * from @Candidates where MeetsEligibility = convert(bit,1);

    Why do you convert the 1 into a bit? just saying 1 works. I know that the data type for MeetsEligibility is a bit and I'm just curious if there are efficiencies is converting explicitly like this or is it just a readability thing?


    Steve
    Ken Davis
    Ken Davis
    SSC-Enthusiastic
    SSC-Enthusiastic (171 reputation)SSC-Enthusiastic (171 reputation)SSC-Enthusiastic (171 reputation)SSC-Enthusiastic (171 reputation)SSC-Enthusiastic (171 reputation)SSC-Enthusiastic (171 reputation)SSC-Enthusiastic (171 reputation)SSC-Enthusiastic (171 reputation)

    Group: General Forum Members
    Points: 171 Visits: 491
    Excellent article. It's very readable with good examples.
    WayneS
    WayneS
    SSCertifiable
    SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)SSCertifiable (6.2K reputation)

    Group: General Forum Members
    Points: 6230 Visits: 10398
    SW_Lindsay (4/20/2010)
    Nice and helpful article - Thanks. Just Curious...

    To select eligible candidates in the first select you say

    select * from @Candidates where MeetsEligibility = convert(bit,1);

    Why do you convert the 1 into a bit? just saying 1 works. I know that the data type for MeetsEligibility is a bit and I'm just curious if there are efficiencies is converting explicitly like this or is it just a readability thing?


    Steve

    Avoiding an "Implicit conversion". The literal 1 is an integer, resulting in the underlying field being converted to an integer to do the match... if there is an index on this field, it won't be used. Converting the 1 to a bit avoids the implicit conversion, and allows use of an index if one is present.

    Personally, I wish there were system variables @@True and @@False of datatype bit, set to 1/0 respectively.

    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, How to ask a question, Performance Problems, Common date/time routines,
    CROSS-TABS and PIVOT tables Part 1 & Part 2, Using APPLY Part 1 & Part 2, Splitting Delimited Strings

    SW_Lindsay
    SW_Lindsay
    SSC-Enthusiastic
    SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)SSC-Enthusiastic (121 reputation)

    Group: General Forum Members
    Points: 121 Visits: 309
    Thanks for the reply and I would agree those constants would be a great additions!
    Andy Lennon
    Andy Lennon
    Ten Centuries
    Ten Centuries (1.4K reputation)Ten Centuries (1.4K reputation)Ten Centuries (1.4K reputation)Ten Centuries (1.4K reputation)Ten Centuries (1.4K reputation)Ten Centuries (1.4K reputation)Ten Centuries (1.4K reputation)Ten Centuries (1.4K reputation)

    Group: General Forum Members
    Points: 1392 Visits: 826
    Michael Meierruth (4/20/2010)
    Wayne,
    You state what I always wanted to hear stated, i.e. that ROW_NUMBER()'s ORDER BY is not the same as the SELECT's ORDER BY. Yet, always - haven't encountered an exception yet, when you perform a SELECT the output is always in the order specified by ROW_NUMBER()'s ORDER BY without the presence of an ORDER BY in the SELECT.
    How do you explain that?


    i had the same question. is there a performance gain with the explicit conversion?

    nvm, answered already Hehe
    Go


    Permissions

    You can't post new topics.
    You can't post topic replies.
    You can't post new polls.
    You can't post replies to polls.
    You can't edit your own topics.
    You can't delete your own topics.
    You can't edit other topics.
    You can't delete other topics.
    You can't edit your own posts.
    You can't edit other posts.
    You can't delete your own posts.
    You can't delete other posts.
    You can't post events.
    You can't edit your own events.
    You can't edit other events.
    You can't delete your own events.
    You can't delete other events.
    You can't send private messages.
    You can't send emails.
    You can read topics.
    You can't vote in polls.
    You can't upload attachments.
    You can download attachments.
    You can't post HTML code.
    You can't edit HTML code.
    You can't post IFCode.
    You can't post JavaScript.
    You can post emoticons.
    You can't post or upload images.

    Select a forum

































































































































































    SQLServerCentral


    Search