Delete Duplicates with Using

Hello,

I run the SQL query below to delete duplicates from a table.  The
subquery is used to identify the duplicated rows (row_num is a BIGSERIAL
column).

/** delete older copies of duplicates */
DELETE FROM table_with_duplicatesAS T
WHERE row_num IN (
    SELECT     T1.row_num
    FROM    table_with_duplicates  AS T1
        JOIN table_with_duplicates AS T2
            ON         T1.column_1 = T2.column_1
                AND T1.column_2 = T2.column_2
                AND T1.column_3 = T2.column_3
                AND T1.row_num < T2.row_num
);

Can anyone tell me how to rewrite that query to use the USING clause and
hopefully remove the subquery?

The documentation mentions USING but there is no example and the only
examples I found online are very trivial.

Thanks,

Igal Sapir
Lucee Core Developer
Lucee.org <http://lucee.org/>