Re: proposal: session server side variables

>
> 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.
>