Error querying postgresql table created in pgAdmin
PostgreSQL implicitly converts all the SQL that you enter into lower case, unless you wrap things in double-quotes in which case you have to get the case exactly right.
Wherever possible, you should avoid needing quotes or other wrapper characters, i.e. don't use special characters in identifier names.  It will only come back to bite you.
create table public.test3
( pid integer
, name character varying(20) 
, primary key (pid)
)