Re: Add column and specify the column position in a table

Emi Lu a écrit :
> I am trying to insert one column to a specific position in a table.
>
> In mysql, I can do:
> . create table test(id varchar(3), name varchar(12));
> . alter table test add column givename varchar(12) after id;
>
>
> I am looking for similar things in postgresql to add a new column to the
> correct position in a table.
>
> Could someone hint me please.
>

There's no similar thing in PostgreSQL. You have to duplicate the table
to do it. You can do it in a transaction :

CREATE TABLE test (id varchar(3), name varchar(12));

then later :

BEGIN;
ALTER TABLE test RENAME TO oldtest;
CREATE TABLE test (id varchar(3), givename varchar(12), name varchar(12));
INSERT INTO test (id, name) SELECT id, name FROM oldtest;
DROP TABLE oldtest;
COMMIT;

Not really interesting if you have really big tables but, in fact, you
shouldn't rely on columns' order.

Regards.

--
Guillaume.