Re: Add column and specify the column position in a table - Mailing list pgsql-sql

From Guillaume LELARGE
Subject Re: Add column and specify the column position in a table
Date
Msg-id 446C0BC0.7050805@gmail.com
Whole thread Raw
In response to Add column and specify the column position in a table  (Emi Lu <emilu@encs.concordia.ca>)
Responses Re: Add column and specify the column position in a table
List pgsql-sql
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.


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