SQL Optimization

  • Good afternoon all,

    trying to optimize a portion of my sql. I've simplified it below, but the portion that it's hang up on is the inner join to the SSICategory, specifically the 2nd part ((n.SSICatyear = year(ep.proceduredate)). Below is a simplified query with the data types of the joins and what I've tried so far is below, but not really making a difference. Could really use some help. Thanks!

    declare @startdate as date
    set @startdate='2016-01-01'

    ;with SSICTE as (

    SELECT distinct
         ep.[VisitId]
        ,n.SSICat
        ,ep.ProcedureDate
         ,ep.proccode

    FROM EncounterProc ep

    inner join SSiCategory n on (n.ICDcode=ep.proccode) and (n.SSICatyear = year(ep.proceduredate))

    Select ssi.visitid, ssi.SSICat, ssi.ProcedureDate, ssi.proccode
    From SSICTE SSI
    where ssi.proceduredate>=@startdate

    Data Types
    n.icdcode = nvarchar(255); 
    ep.proccode = varchar(10); 
    n.ssiCatyear = nvarchar(255); 
    ep.proceduredate = datetime

    I have tried:

    declare @startdate as date
    set @startdate='2016-01-01'

    ;with SSICTE as (

    SELECT distinct
       ep.[VisitId]
       ,n.SSICat
       ,ep.ProcedureDate
         ,ep.proccode

    FROM EncounterProc ep

    inner join SSiCategory n on (n.ICDcode=ep.proccode) and (covert(int,n.SSICatyear) = year(convert(int,ep.proceduredate)))

    n.icdcode = nvarchar(255);
    ep.proccode = varchar(10);

    n.ssiCatyear = nvarchar(255);
    ep.proceduredate = datetime

    Select ssi.visitid, ssi.SSICat, ssi.ProcedureDate, ssi.proccode
    From SSICTE SSI
    where ssi.proceduredate>=@startdate

  • Without data to test with not sure if this would work, here is what I would try:
    DECLARE @startdate AS DATE;
    SET @startdate = '2016-01-01';

    WITH EncounterProc_CTE AS
    (
        SELECT ep.VisitId,
            ep.ProcedureDate,
            ep.proccode,
            YEAR(ep.ProcedureDate) AS ProcedureYear
        FROM EncounterProc AS ep
        WHERE ep.proceduredate >= @startdate
    )
    ,
    SSICTE AS
    (
        SELECT
            ep.VisitId,
            n.SSICat,
            ep.ProcedureDate,
            ep.proccode
        FROM EncounterProc_CTE AS ep
            INNER JOIN SSiCategory AS n
                ON n.ICDcode = ep.proccode
                AND n.SSICatyear = ep.ProcedureYear
        GROUP BY
            ep.VisitId,
            n.SSICat,
            ep.ProcedureDate,
            ep.proccode
    )
    Select ssi.VisitId,
        ssi.SSICat,
        ssi.ProcedureDate,
        ssi.proccode
    From SSICTE AS SSI
    ;

    -------------------------------------------------------------
    we travel not to escape life but for life not to escape us
    Don't fear failure, fear regret.

  • You should generally avoid functions/conversions on fields in ON/WHERE clauses.  You have multiple functions/conversions in your ON clause, which is why you are having problems.

    Part of the issue is that you are storing your data in the wrong format.  A Year is not VARCHAR() data, so it should not be stored in a VARCHAR() field.

    You can address some of the other issues using a calendar table, and you can even construct a partial one on the fly.  You can search for a calendar table to see examples of how this might work.

    Drew

    J. Drew Allen
    Business Intelligence Analyst
    Philadelphia, PA

  • Specifically this stuff:

    (covert(int,n.SSICatyear) = year(convert(int,ep.proceduredate)))

    Is going to kill performance.

    "The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
    - Theodore Roosevelt

    Author of:
    SQL Server Execution Plans
    SQL Server Query Performance Tuning

  • Reforrmat  the SSICat data and not the ep data, since there should be far fewer SSICat rows.

    How is the EncounterProc table clustered?

    Hopefully you don't actually need the distinct, but uncomment it if you do.  Distinct adds overhead because it requires a sort.


    SELECT /*DISTINCT --uncomment if you genuinely require DISTINCT*/
    ep.[VisitId]
    ,n.SSICat
    ,ep.ProcedureDate
    ,ep.proccode

    FROM EncounterProc ep

    INNER JOIN SSiCategory n ON (n.ICDcode=ep.proccode) AND
      ep.proceduredate >= n.SSICatyear + '0101' AND
      ep.proceduredate < cast(convert(int, n.SSICatyear + 1) as varchar(4)) + '0101'

    WHERE ep.proceduredate>=@startdate

    SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".

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