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how does NOT EXISTS work?

  • June 23, 2011 at 5:06 am

    #238333

    Can someone please explain me this.Based on below does it mean that each row out of the result set from the joins is checked against (Select * from table A

    where col10=b.col10) to see if it exists or not?

    select a.col1,b.col2

    from tableA a

    inner join tableB b

    on a.col1=b.col1

    and NOT EXISTS

    ( Select * from table A

    where col10=b.col10)

  • June 23, 2011 at 6:45 am

    #1342980

    Honestly, I don't know if that query will cause RBAR without seeing the DDL for both tables and some sample data to test with.

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