Where is the sql temporary table?

The temporary table you mentioned should consist of two kinds.
The first is a temporary table without a name. This temporary table can be understood as a table formed by a subquery. This type of table has no name. It is related to this sql operation of this session, and other sessions and other sql operations of this session cannot be queried.
The second is a temporary table with a name, a temporary table created during the process. This kind of temporary table always exists during the operation of the process. As long as the process is still executing, the temporary table is in a queryable state. However, the limited scope is the session where the process is located. When the process is completed, the temporary table is released along with the release of the session.
So generally speaking, other sessions cannot check the contents of the temporary table. The temp tablespace of the location, but it should be fine