复杂SQL语句优化提速,该怎么解决

select (select bmdm_name from businessAreaConcentrade  where bmdm = d.companyid) companyid,to_char(d.endorOverDate,'yyyy-mm') year_month,s.scaleofmarkdes,count(distinct d.claimno) countnumfrom (  select claimno,  substr(','||tt.CHECKSCALEOFMARK,  instr(','||tt.CHECKSCALEOFMARK,',',1,temp.rn)+1,instr(tt.CHECKSCALEOFMARK,',',1,temp.rn)  -instr(','||tt.CHECKSCALEOFMARK,',',1,temp.rn)) CHECKSCALEOFMARK,  checkdate,ENDORSCALEOFMARK,ENDORDATEfrom claimScaleOfmarks tt,  (select rownum rn from dual connect by rownum<35)tempwhere length(tt.CHECKSCALEOFMARK)-length(replace(tt.CHECKSCALEOFMARK,','))>=temp.rn --order by 1,temp.rn) c,scaleOfmarksPara s,claiminfo  dwhere c.claimno=d.claimno  and c.checkScaleOfmark=s.id and (trunc(d.endorOverDate,'DD') >= to_date('2012-01-01','yyyy/mm/dd') and trunc(d.endorOverDate,'DD') <= to_date('2012-05-02','yyyy/mm/dd') )and (c.checkScaleOfmark is not null) or (c.endorScaleOfmark is not null)and s.score<=0group by d.companyid,to_char(d.endorOverDate,'yyyy-mm'),s.scaleofmarkdesorder by d.companyid,to_char(d.endorOverDate,'yyyy-mm'),s.scaleofmarkdes