sql - Alter data type of a column to serial

Question

In pgsql, is there a way to have a table of several values, and choose one of them (say, other_id), find out what its highest value is and make every new entry that is put in the table increment from that value.

I suppose this was just too easy to have had a chance of working..

ALTER TABLE address ALTER COLUMN new_id TYPE SERIAL

____________________________________ 
ERROR:  type "serial" does not exist

Thanks much for any insight!

Answer 1

Look into postgresql documentation of datatype serial. Serial is only short hand.

CREATE TABLE tablename (
    colname SERIAL
);

is equivalent to specifying:

CREATE SEQUENCE tablename_colname_seq;
CREATE TABLE tablename (
    colname integer NOT NULL DEFAULT nextval('tablename_colname_seq')
);
ALTER SEQUENCE tablename_colname_seq OWNED BY tablename.colname;