SQL query help

  • Can someone help in building a query through which i can determine if a table has duplicate rows and what are the duplicate rows?

  • Just google on "sql duplicate records rows" and you will probably find hundreds of these scripts.

    [font="Verdana"]Markus Bohse[/font]

  • Or do a search in the little box near the top of the page. You'll find tons of discussions and articles and scripts on the topic, all on this site.

    "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

  • I'll make it easy for you 🙂

    -- Identify Duplicate Rows

    select SomeColumn,SomeKey

    from MyTable

    group by SomeColumn,SomeKey

    having count(*) > 1;

    -- Nuke Duplicate Rows

    alter table MyTable

    add RowID int identity(1,1)

    delete from MyTable

    where RowID NOT IN

    (select min(RowID) from MyTable

    group by SomeColumn,SomeKey)

    alter table MyTable

    drop column RowID

    go

    -- Verify

    select SomeColumn,SomeKey

    from MyTable

    group by SomeColumn,SomeKey

    having count(*) > 1;

Viewing 4 posts - 1 through 3 (of 3 total)

You must be logged in to reply to this topic. Login to reply