select
  INST_ID,                                 -- INST_ID NUMBER
  HS_SESSION_ID,                           -- HS_SESSION_ID NUMBER
  AGENT_ID,                                -- AGENT_ID NUMBER
  SID,                                     -- SID NUMBER
  decode(                                  -- DB_LINK VARCHAR2(128)
    AGENT_TYPE, 1, NULL, DB_LINK),
  decode(                                  -- DB_LINK_OWNER NUMBER
    AGENT_TYPE, 1, to_number(NULL), DB_LINK_OWNER),
  SES_STARTTIME                            -- STARTTIME DATE
from
  X$HS_SESSION