select
  d.inst_id,                               -- INST_ID NUMBER
  d.indx,                                  -- EVENT# NUMBER
  d.kslednam,                              -- EVENT VARCHAR2(64)
  s.kslsesmaxdur,                          -- WAIT_TIME_MILLI NUMBER
  s.kslsesval,                             -- WAIT_COUNT NUMBER
  decode(                                  -- LAST_UPDATE_TIME VARCHAR2(64)
    s.kslsesval, 0, NULL, s.kslsestimestamp) 
from
  x$kslseshist s,
  x$ksled d
where
  s.kslsesenum = d.indx