Organically cancel a resultset from proc if rowcount is zero?

  • RBarryYoung (5/16/2012)


    I'm still trying to figure out what it means to "Organically Cancel" a resultset. Does that mean that it comes with a sprig of broccoli or something? 😀

    Only if the server is running on batteries recharged with a solar panel.

    The probability of survival is inversely proportional to the angle of arrival.

  • RBarryYoung (5/16/2012)


    I'm still trying to figure out what it means to "Organically Cancel" a resultset. Does that mean that it comes with a sprig of broccoli or something? 😀

    methink DBCC TIMEWARP would have come in handy. run the select, check for records and timewarp to right before you ran the select...:)

    ----------------------------------------------------------------------------------
    Your lack of planning does not constitute an emergency on my part...unless you're my manager...or a director and above...or a really loud-spoken end-user..All right - what was my emergency again?

  • Matt Miller (#4) (5/16/2012)


    RBarryYoung (5/16/2012)


    I'm still trying to figure out what it means to "Organically Cancel" a resultset. Does that mean that it comes with a sprig of broccoli or something? 😀

    methink DBCC TIMEWARP would have come in handy. run the select, check for records and timewarp to right before you ran the select...:)

    Heh. 🙂

    [font="Times New Roman"]-- RBarryYoung[/font], [font="Times New Roman"] (302)375-0451[/font] blog: MovingSQL.com, Twitter: @RBarryYoung[font="Arial Black"]
    Proactive Performance Solutions, Inc.
    [/font]
    [font="Verdana"] "Performance is our middle name."[/font]

  • Knowing that it probably wouldn't work, I was playing around with this anyway and of course it didn't work.

    SET ANSI_NULLS ON

    GO

    SET QUOTED_IDENTIFIER ON

    GO

    CREATE PROCEDURE dbo.Test AS

    BEGIN

    DECLARE @sql NVARCHAR(100)

    PRINT 'Entering SP'

    SET @sql = 'KILL @@SPID'

    EXEC (@SQL)

    PRINT 'Exiting SP'

    END

    GO

    EXEC dbo.Test

    This is the erxception it throws:

    Entering SP

    Msg 102, Level 15, State 1, Line 1

    Incorrect syntax near '@@SPID'.

    Exiting SP

    Anyone care to suggest why it doesn't? I know that the @@SPID is probably different for the dynamic SQL session than for the SP session (I tried using KILL that way too and it also did not work).


    My mantra: No loops! No CURSORs! No RBAR! Hoo-uh![/I]

    My thought question: Have you ever been told that your query runs too fast?

    My advice:
    INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
    The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.

    Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
    Since random numbers are too important to be left to chance, let's generate some![/url]
    Learn to understand recursive CTEs by example.[/url]
    [url url=http://www.sqlservercentral.com/articles/St

  • dwain.c (5/17/2012)


    Knowing that it probably wouldn't work, I was playing around with this anyway and of course it didn't work.

    SET ANSI_NULLS ON

    GO

    SET QUOTED_IDENTIFIER ON

    GO

    CREATE PROCEDURE dbo.Test AS

    BEGIN

    DECLARE @sql NVARCHAR(100)

    PRINT 'Entering SP'

    SET @sql = 'KILL @@SPID'

    EXEC (@SQL)

    PRINT 'Exiting SP'

    END

    GO

    EXEC dbo.Test

    This is the erxception it throws:

    Entering SP

    Msg 102, Level 15, State 1, Line 1

    Incorrect syntax near '@@SPID'.

    Exiting SP

    Anyone care to suggest why it doesn't? I know that the @@SPID is probably different for the dynamic SQL session than for the SP session (I tried using KILL that way too and it also did not work).

    Try this, Dwain:

    SET ANSI_NULLS ON

    GO

    SET QUOTED_IDENTIFIER ON

    GO

    CREATE PROCEDURE dbo.Test AS

    BEGIN

    DECLARE @sql NVARCHAR(100), @SPID smallint

    SELECT 'Entering SP' AS 'Where are we?', @@SPID AS '@@SPID'

    SELECT @SPID = @@SPID

    SET @sql = 'SELECT @@SPID AS ''@@SPID in EXEC call''; KILL ' + CAST ( @SPID AS varchar )

    EXEC (@SQL)

    SELECT 'Exiting SP' AS 'Where are we?'

    END

    GO

    EXEC dbo.Test

    --------------------------------------------------------------------------
    A little knowledge is a dangerous thing (Alexander Pope)
    In order for us to help you as efficiently as possible, please read this before posting (courtesy of Jeff Moden)[/url]

  • Here's how I would probably do it:

    CREATE PROC pr_OrganicDissapearance AS

    BEGIN TRY

    ;WITH yourQuery As

    (

    SELECT *

    FROM yourTable

    WHERE (yourConditions)

    -- etc ...

    )

    SELECT *

    FROM yourQuery

    WHERE -1 < ( 1 / (SELECT COUNT(*) FROM yourQuery) )

    END TRY

    BEGIN CATCH

    RETURN -- suppress the error, and the resultset

    END CATCH

    Does that do it? 😀

    [font="Times New Roman"]-- RBarryYoung[/font], [font="Times New Roman"] (302)375-0451[/font] blog: MovingSQL.com, Twitter: @RBarryYoung[font="Arial Black"]
    Proactive Performance Solutions, Inc.
    [/font]
    [font="Verdana"] "Performance is our middle name."[/font]

  • Very slick try, but it doesn't seem to work:

    USE tempdb

    GO

    CREATE TABLE tmp (a int)

    INSERT tmp VALUES (1)

    go

    CREATE PROC pr_OrganicDissapearance AS

    SELECT a FROM tmp WHERE a = 1

    BEGIN TRY

    ;WITH yourQuery As

    (

    SELECT a

    FROM tmp

    WHERE a = 2

    )

    SELECT *

    FROM yourQuery

    WHERE -1 < ( 1 / (SELECT COUNT(*) FROM yourQuery) )

    END TRY

    BEGIN CATCH

    --cannot return here because OP wants additional result set out

    --PRINT 'no records so no resultset?'

    END CATCH

    SELECT a FROM tmp WHERE a = 1

    GO

    EXEC pr_OrganicDissapearance

    GO

    drop PROC pr_OrganicDissapearance

    GO

    DROP TABLE tmp

    GO

    a

    -----------

    1

    (1 row(s) affected)

    a

    -----------

    (0 row(s) affected)

    a

    -----------

    1

    (1 row(s) affected)

    Best,
    Kevin G. Boles
    SQL Server Consultant
    SQL MVP 2007-2012
    TheSQLGuru on googles mail service

  • Jan Van der Eecken (5/17/2012)


    dwain.c (5/17/2012)


    Knowing that it probably wouldn't work, I was playing around with this anyway and of course it didn't work.

    SET ANSI_NULLS ON

    GO

    SET QUOTED_IDENTIFIER ON

    GO

    CREATE PROCEDURE dbo.Test AS

    BEGIN

    DECLARE @sql NVARCHAR(100)

    PRINT 'Entering SP'

    SET @sql = 'KILL @@SPID'

    EXEC (@SQL)

    PRINT 'Exiting SP'

    END

    GO

    EXEC dbo.Test

    This is the erxception it throws:

    Entering SP

    Msg 102, Level 15, State 1, Line 1

    Incorrect syntax near '@@SPID'.

    Exiting SP

    Anyone care to suggest why it doesn't? I know that the @@SPID is probably different for the dynamic SQL session than for the SP session (I tried using KILL that way too and it also did not work).

    Try this, Dwain:

    SET ANSI_NULLS ON

    GO

    SET QUOTED_IDENTIFIER ON

    GO

    CREATE PROCEDURE dbo.Test AS

    BEGIN

    DECLARE @sql NVARCHAR(100), @SPID smallint

    SELECT 'Entering SP' AS 'Where are we?', @@SPID AS '@@SPID'

    SELECT @SPID = @@SPID

    SET @sql = 'SELECT @@SPID AS ''@@SPID in EXEC call''; KILL ' + CAST ( @SPID AS varchar )

    EXEC (@SQL)

    SELECT 'Exiting SP' AS 'Where are we?'

    END

    GO

    EXEC dbo.Test

    Now that's an interesting approach! Who'da thunk it!


    My mantra: No loops! No CURSORs! No RBAR! Hoo-uh![/I]

    My thought question: Have you ever been told that your query runs too fast?

    My advice:
    INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
    The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.

    Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
    Since random numbers are too important to be left to chance, let's generate some![/url]
    Learn to understand recursive CTEs by example.[/url]
    [url url=http://www.sqlservercentral.com/articles/St

  • "SET @sql = 'KILL @@SPID'

    EXEC (@SQL)"

    Killing ones self is a depressing solution.

    The probability of survival is inversely proportional to the angle of arrival.

  • Thanks for the test, Kevin.

    Hmm, I wonder why that didn't work? ...

    [font="Times New Roman"]-- RBarryYoung[/font], [font="Times New Roman"] (302)375-0451[/font] blog: MovingSQL.com, Twitter: @RBarryYoung[font="Arial Black"]
    Proactive Performance Solutions, Inc.
    [/font]
    [font="Verdana"] "Performance is our middle name."[/font]

  • sturner (5/17/2012)


    "SET @sql = 'KILL @@SPID'

    EXEC (@SQL)"

    Killing ones self is a depressing solution.

    Ah yes, but suicide by SP is less depressing than say jumping off a building.

    Perhaps there's another solution akin to:

    SET SP_CLOAKING ON

    That way if you can't see it maybe it isn't really there.


    My mantra: No loops! No CURSORs! No RBAR! Hoo-uh![/I]

    My thought question: Have you ever been told that your query runs too fast?

    My advice:
    INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
    The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.

    Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
    Since random numbers are too important to be left to chance, let's generate some![/url]
    Learn to understand recursive CTEs by example.[/url]
    [url url=http://www.sqlservercentral.com/articles/St

  • RBarryYoung (5/17/2012)


    Thanks for the test, Kevin.

    Hmm, I wonder why that didn't work? ...

    Well I looked at the estimated and actual query plans for several different versions of my attempt, and I have come to the conclusion that SQL Server is creating the result-set and sending it (the headers) to the client before it even knows if it will find any rows. Indeed, before it has evaluated any part of the query except what the column-set will be.

    So that makes it seem pretty clear that it cannot be done without a preliminary query to test it.

    [font="Times New Roman"]-- RBarryYoung[/font], [font="Times New Roman"] (302)375-0451[/font] blog: MovingSQL.com, Twitter: @RBarryYoung[font="Arial Black"]
    Proactive Performance Solutions, Inc.
    [/font]
    [font="Verdana"] "Performance is our middle name."[/font]

  • RBarryYoung (5/17/2012)


    RBarryYoung (5/17/2012)


    Thanks for the test, Kevin.

    Hmm, I wonder why that didn't work? ...

    Well I looked at the estimated and actual query plans for several different versions of my attempt, and I have come to the conclusion that SQL Server is creating the result-set and sending it (the headers) to the client before it even knows if it will find any rows. Indeed, before it has evaluated any part of the query except what the column-set will be.

    So that makes it seem pretty clear that it cannot be done without a preliminary query to test it.

    I think there is kinda a "contract" if you will that a sproc will provide outputs when a SELECT is executed, even if it errors out.

    BTW, I also tried this for the error handling and it responded similarly:

    IF @@ERROR <> 0

    BEGIN

    PRINT 'does this work? ... nope'

    END

    Best,
    Kevin G. Boles
    SQL Server Consultant
    SQL MVP 2007-2012
    TheSQLGuru on googles mail service

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