Re: [HACKERS] proposal: session server side variables
| От | Pavel Stehule |
|---|---|
| Тема | Re: [HACKERS] proposal: session server side variables |
| Дата | |
| Msg-id | CAFj8pRAWhhDkbq4k_aCOZeTNj0tg2bE370=J2_9dVSHfueWK+A@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: [HACKERS] proposal: session server side variables (Fabien COELHO <coelho@cri.ensmp.fr>) |
| Ответы |
Re: [HACKERS] proposal: session server side variables
|
| Список | pgsql-hackers |
If you do not have expectations, then all is fine.(1) Having some kind of variable, especially in interactive mode, allows to
manipulate previous results and reuse them later, without having to resort
to repeated sub-queries or to retype non trivial values.
Client side psql :-variables are untyped and unescaped, thus not very
convenient for this purpose.
You can currently (ab)use user defined GUCs for this.
How? It seems that I have missed the syntax to assign the result of a query to a user-defined guc, and to reuse it simply in a query.
postgres=# select set_config('myvar.text', (select current_timestamp::text), false);
+-------------------------------+
| set_config |
+-------------------------------+
| 2016-12-31 18:56:42.894246+01 |
+-------------------------------+
(1 row)
Time: 0,448 ms
postgres=# select current_setting('myvar.text');
+-------------------------------+
| current_setting |
+-------------------------------+
| 2016-12-31 18:56:42.894246+01 |
+-------------------------------+
(1 row)
--
Fabien.
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