[ivanhoe]

a mozes i nesto ovako:

CREATE TEMPORARY TABLE `bla` 
     SELECT * FROM `postparsed` GROUP BY `postid`;
TRUNCATE TABLE `postparsed`;
INSERT INTO `postparsed` 
     SELECT * FROM `bla`;

EDIT: u stvari jos pametnije bi bilo da se umesto SELECT * navedu imena svih polja, sa DISTINCT `postid`, umesto GROUP BY dela