can you please point at my mistake? im doing

with au as (SELECT set_config(
  'request.jwt.claims',
  '{ "sub": "MY UID from auth table ", "email": "MY EMAIL from auth table" }',
  false
))
select * from auth.uid();

and it always returns

null

WITH-statments are generally used with common table expressions (CTEs) in order to setup something like a temporary table which you can then use in a select

Hm. I thought each select overwrites the previous select in supabase.io dashboard

the Supabase dashboard is just a client in order to interact with the PostgreSQL database - it does NOT modify the actual behavior of the database. That is, regardless of whether you use the Supabase dashboard or another client to connect to the DB (e.g. pgAdmin, TablePlus, Datagrip, etc), you would get the exact same behavior. The only possible difference is that the Supabase dashboard uses the supabase_admin user by default so you get permission to do more things

SELECT set_config(
  'request.jwt.claims',
  '{ "sub": "...", "email": "..." }',
  false
);
select * from auth.uid();

returns

Success. No rows returned

ok, I see what you are saying, I cannot tell you why it behaves like that...it seems like a bug to me