text: 
  CREATE OR REPLACE FUNCTION s_user_id_by_email(
      email_value TEXT
  )
  
  RETURNS BIGINT
  
  LANGUAGE SQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL UNSAFE
  
  AS $$
  
  SELECT tu_id
  FROM t_users
  WHERE tu_email = email_value
  LIMIT 1
  
  $$;
  