Grrr!... Jeg skriver her for ikke at skulle læse manualer
Men tak.
mysql> ALTER TABLE t1 CHANGE a b INTEGER;
If you want to change a column's type but not the name, CHANGE syntax still requires an old and new column name, even if they are the same. For example: mysql> ALTER TABLE t1 CHANGE b b BIGINT NOT NULL;
Dvs:
alter table forum_traade change dato dato varchar(20);
i mit tilfælde.