Example of how to delete duplicate entry

gistfile1.sql

-- DELETE duplicate entry
BEGIN;
    CREATE 
     TABLE tempT SELECT  MIN(id) id
                   FROM L_table
                  GROUP BY l_field, etc ASC;
    DELETE 
      FROM L_table
     WHERE id NOT IN (SELECT id
                        FROM tempT);
 
      DROP TABLE tempT;
  COMMIT
END;