How to delete duplicate rows in SQL Server?

Question

How can I delete duplicate rows where no unique row id exists?

My table is

col1  col2 col3 col4 col5 col6 col7
john  1          


        

Answer 1

If you have no references, like foreign keys, you can do this. I do it a lot when testing proofs of concept and the test data gets duplicated.

SELECT DISTINCT [col1],[col2],[col3],[col4],[col5],[col6],[col7]

INTO [newTable]

FROM [oldTable]

Go into the object explorer and delete the old table.

Rename the new table with the old table's name.