Here is another good article on removing duplicates. It discusses why its hard: "SQL is based on relational algebra, and duplicates cannot occur in relational algebra, because duplicates are not allowed in a set." The temp table solution, and two mysql examples.

Jul 3, 2017 · Remove all duplicates, but the very first ones (with min ID) should work equally in other SQL servers, like Postgres: DELETE FROM table WHERE id NOT IN ( select min(id) from table group by col1, col2, col3, col4, col5, col6, col7 )

Sep 12, 2010 · It does not answer your question and remove the duplicates but it helps give a count which might be relevant: COUNT(*) - COUNT(DISTINCT name) AS 'duplicate name' – JPK Commented May 4, 2016 at 10:27

Apr 15, 2013 · SQL remove duplicate rows based on other rows ... Remove duplicates on specific rows in oracle query. Hot ...

Jul 14, 2009 · The two most common ways I've seen are adding Distinct to Top 1 or you could add a column to the query that is unique so that sql would have a way to choose which record to pick in what would otherwise be a tie.

You can use the DISTINCT in SQL Server to get the distinct records only. Apart from this you can also use the ROW_NUMBER (Transact-SQL) function to get the distinct result by assigning the numbers to a result set. The syntax of row_number() is as shown below. ROW_NUMBER ( ) OVER ( [ PARTITION BY value_expression , ... [ n ] ] order_by_clause )

Sep 18, 2008 · Then copy the keys, but eliminate the duplicates. SELECT DISTINCT t1.* INTO holddups FROM t1, holdkey WHERE t1.col1 = holdkey.col1 AND t1.col2 = holdkey.col2 In your keys you have now unique keys. Check if you don't get any result: SELECT col1, col2, count(*) FROM holddups GROUP BY col1, col2 Delete the duplicates from the original table:

How can I remove the duplicates in siteName column? I want to leave only the updated one based on date column. In the example output above, I need the rows 1, 3, 6, 10

Jan 19, 2017 · If you just want to return the most recent row for name, you can use: select t.* from t where t.date = (select max(t2.date) from t t2 where t2.name = t.name);

A little off topic, but if you want to migrate the data to a new table, and the possible duplicates are in the original table, and the column possibly duplicated is not an id, a GROUP BY will do: INSERT INTO TABLE_2 (name) SELECT t1.name FROM TABLE_1 t1 GROUP BY t1.name