Summary
To select all duplicate records from a table and delete them use the queries below:
SELECT * FROM table_with_duplicates WHERE ROWID NOT IN
(SELECT MIN (ROWID) FROM table_with_duplicates
GROUP BY col1, col2, col3);
DELETE FROM table_with_duplicates WHERE ROWID NOT IN
(SELECT MIN (ROWID) FROM table_with_duplicates
GROUP BY col1, col2, col3);
