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sql-serverrdbms

How to detect duplicate rows in a SQL Server table?

What is the most efficient way to detect duplicates in a 10 column / 50K row table? I'm using MSSQL 8.0

Solution

  • To show an example of what others have been describing:

    SELECT
    Col1, -- All of the columns you want to dedupe on
    Col2, -- which is not neccesarily all of the columns
    Col3, -- in the table
    Col4,
    Col5,
    Col6,
    Col7,
    Col8,
    Col9,
    Col10
FROM
    MyTable
GROUP BY
    Col1,
    Col2,
    Col3,
    Col4,
    Col5,
    Col6,
    Col7,
    Col8,
    Col9,
    Col10
HAVING
    COUNT(*) > 1