sql优化

Question

请问下面的SQL如何优化：
fx_deliverychecklist表2146949行，fx_accountdetails表3388132行
update fx_deliverychecklist a set a.checkscale=nvl(a.checkscale,0)+nvl((select b.checkscale from fx_accountdetails b where a.id=b.detailid and trim(a.deliveryid)=b.invoiceid and b.checkcash='F00006757'),0)
where exists
(select c.invoiceid from fx_accountdetails c where c.checkcash='F00006757' and trim(a.deliveryid)=c.invoiceid)

Answer 1

update fx_deliverychecklist a 
  set a.checkscale=nvl(a.checkscale,0)+(select nvl(b.checkscale,0) 
  from fx_accountdetails b 
 where b.detailid = a.id 
   and b.checkcash = 'F00006757'
   and b.invoiceid = trim(a.deliveryid) )
where exists
( select 1 from fx_accountdetails c 
   where c.detailid = a.id
     and c.checkcash='F00006757' 
     and trim(a.deliveryid)=c.invoiceid);-- 好像没有优化的余地啦...........

Answer 2

update fx_deliverychecklist a 
  set a.checkscale=nvl(a.checkscale,0)+(select nvl(b.checkscale,0) 
                      from fx_accountdetails b 
                     where b.detailid = a.id 
                       and b.checkcash = 'F00006757'
                       and b.invoiceid = trim(a.deliveryid) )
where exists
( select 1 from fx_accountdetails c 
   where c.detailid = a.id
     and c.checkcash = 'F00006757' 
     and c.invoiceid = trim(a.deliveryid));