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SQL optimization

  • February 13, 2004 at 3:37 am

    #107539

    how to optimize following qry which running on tables with million records

    select * from tab1 where ID not in (select ID from tab2)

     

     

  • February 13, 2004 at 4:40 am

    #493969

    Use left outer join, and filter out the match pairs

    select t1.* from tab1 t1

    left outer join tab2 t2 on t2.ID=t1.ID

    where t2.ID is null

    Hope this would help

    Thanx

     

  • February 13, 2004 at 1:40 pm

    #494059

    Do you really need to retrieve EVERYTHING? (SELECT *)

    If not, change the * to a list of the columns that you really need.

     

    -SQLBill

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