Re: Insert output query to a column from a joined table in PostgreSQL 9.1 - Mailing list pgsql-novice

On Wed, Feb 13, 2013 at 7:35 PM, Zach Seaman <znseaman@gmail.com> wrote:
> I'm fairly new to PostgreSQL 9.1 and would like to set each of `CASE WHEN`
> clauses to new columns in table `s` after joining to table `t`.

Take a look at the UPDATE ... FROM ... construction
http://www.postgresql.org/docs/9.2/static/sql-update.html.

Here is the fast example from the documentation:

UPDATE employees SET sales_count = sales_count + 1
FROM accounts
WHERE accounts.name = 'Acme Corporation'
AND employees.id = accounts.sales_person;

You can do JOINs in FROM here. Do not forget to alias updated table if
it is used in FROM.

>
> This is my query:
>
> `SELECT s.tipo, s.mod,
> CASE WHEN s.tipo = 1 THEN t.bsolidokgd
>             WHEN s.tipo = 2 THEN t.osolidokgd
>             ELSE t.osolidokgd
>     END AS solidokgd,
>     CASE WHEN s.tipo = 1 THEN t.bbiolld
>             WHEN s.tipo = 2 THEN t.obiolld
>             ELSE t.obiolld
>     END AS biolld,
>     CASE WHEN s.tipo = 1 THEN t.bbiogasm3d
>             WHEN s.tipo = 2 THEN t.obiogasm3d
>             ELSE t.obiogasm3d
>     END AS biogasm3d
> FROM bmc.sisinst s INNER JOIN bmc.temperadoest t ON s.mod = t.mod;`
>
> Is there a way to `INSERT INTO` or `UPDATE` table `s` with a `CASE WHEN`
> clause from table `t`?
>
> Thanks again for all the help,
>
> --
> Zach Seaman

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