Today to make a parameter optional, the user needs to have a workaround in the query logic itself. For example:

select count(0)
from queries
where 'All' = '{{org_id}}' or org_id::varchar = '{{org_id}}'

In this case when the value of org_id is All, then we don't filter by it. It will be great if the user could mark a whole section as optional if no parameter is provided. The templating language we use (Mustache) actually supports this:

select count(0)
from queries
{{#org_id}}
where 'All' = '{{org_id}}' or org_id::varchar = '{{org_id}}'
{{/org_id}}

If no value for {{org_id}} is provided, then the section between {{#org_id}} and {{/org_id}} won't be rendered. So in theory, we can just allow for passing empty values for parameters and it works.

This has two issues though:

1. Any false-y value will make this section not render. Including 0 (zero), which might be acceptable in some cases.
2. This might make the implementation of Move parameters merging to the backend and make it safe #2904 more complicated.

We should probably take this into account when implementing #2904, and revisit once it's indeed implemented.