Re: INSERT RETURNING with values other than inserted ones. - Mailing list pgsql-general

From Richard Dunks
Subject Re: INSERT RETURNING with values other than inserted ones.
Date
Msg-id 7356F383-1437-4FEF-9466-25892F06E294@gmail.com
Whole thread Raw
In response to INSERT RETURNING with values other than inserted ones.  (Aleksandr Furmanov <aleksandr.furmanov@gmail.com>)
Responses Re: INSERT RETURNING with values other than inserted ones.
List pgsql-general
If you're just replicating the data from table A into table B, why does it need its own ID number? Wouldn't the table A
IDsuffice? 

I'd recommend using the following:

CREATE TABLE b AS ( SELECT * FROM a );

This way, you only define the columns and insert the data once, then let Postgres do the rest for you. Obviously if you
needto have a separate table B ID, you can alter as necessary.  

Good luck,
Richard Dunks

On Jun 10, 2013, at 7:29 PM, Aleksandr Furmanov <aleksandr.furmanov@gmail.com> wrote:

> Hello,
> I want to insert new values into target table 'a' from source table 'b', and then update table 'b' with ids from
table'a', somewhat like: 
>
> CREATE TABLE a(id SERIAL, name TEXT);
> INSERT INTO a (name) VALUES('Jason');
> INSERT INTO a (name) VALUES('Peter');
>
> CREATE TABLE b(row_id serial, id INT, name TEXT);
> INSERT INTO b (name) VALUES('Jason');
> INSERT INTO b (name) VALUES('Peter');
>
>
> WITH inserted AS (INSERT INTO a (name) SELECT b.name FROM b WHERE b.name = name RETURNING a.id)
>  UPDATE b SET id = inserted.id FROM inserted WHERE inserted.row_id = b.row_id;
>
> However this would not work for obvious reason:
>
> WHERE inserted.row_id = b.row_id is invalid because RETURNING clause cannot return row_id.
> What can be returned are only columns of 'a', but they are insufficient to identify matching records of 'b'.
>
> So the question is - what to put in WHERE clause to match RETURNING with rows being inserted from 'b'?
>
> Thanks!
>
> --
> Aleksandr Furmanov
>
>
>
> --
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