0 - 2 of 2 tags for scalar subqueries

Hi
I looked in the manual SQL Data Manipulation Language page 38. There is an example that I cannot make work.
(Very Simplified!!) here is what I am trying to do:

Select 1; ===> result in "1"

select 2; ===> result in "2"

now I Try to :

Select (Select 1), (Select 2); ===> I get the error message:

SELECT Failed. [3706] Syntax error; expected something between '(' and 'SELECT' Keyword.

on page 38 in the manual it says:
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The commonly known technique to pass parameters to SQL statements at the system or session level utilizes tables (permanent or global temporary tables).
In this blog post, I'll show better performing techniques for system and user level variables using views and QueryBanding.
These solutions are based on TD13, but can also be used pre-TD13, although performance might be worse.