Mine

CREATE TEMPORARY TABLE temp(zipcode varchar(5) NOT NULL default '', city varchar(30) NOT NULL default '', county varchar(30) NOT NULL default '', state varchar(30) NOT NULL default '', areacode varchar(8) NOT NULL default '') TYPE=HEAP;INSERT INTO temp(zipcode,city,county,state,areacode) SELECT DISTINCT city FROM states;DELETE FROM states;INSERT INTO states(zipcode,city,county,state,areacode) SELECT * FROM temp;