A reader, April 28, 2021 - 12:04 pm UTC
Those views does Not provide information about other databases. For example (query other other views you mentioned have the same results in the same database):
SQL> select distinct DBID from AWR_ROOT_CELL_DB;
which means we cannot get other DBs' data.
Qinsheng Zhu, April 30, 2021 - 12:47 pm UTC
Now I know what's wrong with my query.
DBID always the ID of current database. What I need is actually in the databases. They should be SRC_DBID or SRC_DBNAME.
SELECT DISTINCT SRC_DBNAME from AWR_ROOT_CELL_DB will list all the databases on the cluster.
Thank you for your help. Questions answered.