-- This example queries the DBA_PDBS view and the CDB_USERS view from the root to show the users in each PDB. 
-- The query uses p.PDB_ID > 2 to avoid showing the users in the root and the seed.

COLUMN PDB_NAME FORMAT A15
COLUMN USERNAME FORMAT A30
 
SELECT p.PDB_ID, p.PDB_NAME, u.USERNAME 
  FROM DBA_PDBS p, CDB_USERS u
  WHERE p.PDB_ID > 2 AND
        p.PDB_ID = u.CON_ID
  ORDER BY p.PDB_ID;

font:
https://docs.oracle.com/database/121/ADMIN/cdb_mon.htm#ADMIN13939

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