How does one eliminate duplicates rows from a table?

Here's how you remove the duplicate rows before the primary key or unique indexes can be created:

DELETE FROM our_table
WHERE rowid not in
(SELECT MIN(rowid)
FROM our_table
GROUP BY column1, column2, column3... ;

Here column1, column2, column3 constitute the identifying key for each record.
Be sure to replace our_table with the table name from which you want to remove the duplicate rows. The GROUP BY is used on the columns that make the primary key for the table. This script deletes each row in the group after the first row.