Argument in SQL

Hello,

I have a SQL, something like this:

...WHERE p.post_type = 'myposttype'
    AND g.ID = 'arg1'...

arg1 is a number, it is the ID of another custom post type. If I replace with the actual ID, query works fine.

How should I reference this in the SQL and in the shortcode?
These do not work:
SQL: ...AND g.ID = {arg1}...
In a page: [gvn_schart_2 id="605" arg1="41"]

Please check it out,

Thank you,
Kostas