Query to return only test sets with failed defects

Hi, I've got the query below which currently returns all test sets with failed defects linked to them, what I need it to do is return the test sets which only have failed defects, currently some test sets still have open defects.

SELECT REL.REL_NAME         as 'Release'
     , TST.TS_NAME          as 'Test Name'
     , TCY.TC_ACTUAL_TESTER as 'Tester'
     , CYC.CY_CYCLE         as 'Test Set'
     , TCY.TC_STATUS        as 'Test Exec Status'
     , BUG.BG_BUG_ID        as 'Defect ID'
     , BUG.BG_STATUS        as 'Defect Status'
     , BUG.BG_SEVERITY      as 'Defect Severity'
     , BUG.BG_PRIORITY      as 'Defect Priority'
  FROM TEST           TST
     , TESTCYCL       TCY
     , RELEASES       REL
     , RELEASE_CYCLES RCY
     , CYCLE          CYC
     , LINK           LIK
     , BUG            BUG
 WHERE TCY.TC_STATUS      = 'Failed'
   AND LIK.LN_ENTITY_TYPE = 'TESTCYCL'
   AND BUG.BG_STATUS      = 'Closed'
   AND TST.TS_TEST_ID     = TCY.TC_TEST_ID
   AND TCY.TC_CYCLE_ID    = CYC.CY_CYCLE_ID
   AND REL.REL_NAME       = 'SR6'
   AND REL.REL_ID         = RCY.RCYC_PARENT_ID
   AND CYC.CY_ASSIGN_RCYC = RCY.RCYC_ID
   AND TCY.TC_TESTCYCL_ID = LIK.LN_ENTITY_ID
   AND LIK.LN_BUG_ID      = BUG.BG_BUG_ID
ORDER BY CYC.CY_CYCLE

 p.s. I realise it's probably not the best structured query, but it works for me...well sort of :)

Thanks

Nick