"Jens-Wolfhard Schicke" <j.schicke@asco.de> writes:
> \h alter table
> is missing the syntax for the command
> alter table the_table alter column the_column type varchar(175);
Maybe you're using an old psql?  My 8.2 psql shows
regression=> \h alter table
Command:     ALTER TABLE
Description: change the definition of a table
Syntax:
ALTER TABLE [ ONLY ] name [ * ]
    action [, ... ]
...
where action is one of:
...
    ALTER [ COLUMN ] column TYPE type [ USING expression ]
...
            regards, tom lane