merge 多条数据一起处理的问题，急急急急急急急！~~~
merge into hy_wldw a
using (select * from jh_jk_order where TRANSID in('646','645')) b
on (a.dwno =b.SELLERID)
when matched then
  update
  set a.dwmc = b.sname,
  a.dwlx = '2',
  a.dz = b.saddress,
  a.cs = decode(b.FROMDISTRICT, null, b.FROMCITY, b.FROMDISTRICT),
  a.sf = b.FROMPROV,
  a.lxr = b.sname,
  a.dh = b.SMOBILEPHONE,
  a.sjno = b.SELLERID,
  a.yzbm = '1',
  a.xtfl = '1'
when not matched then
  insert
  ( dwmc, dwlx, dz, cs, sf, lxr, dh, sjno, yzbm, xtfl)
  values
  (
  b.SNAME,
  '2',
  b.SADDRESS,
  decode(b.FROMDISTRICT, null, b.FROMCITY, b.FROMDISTRICT),
  b.FROMPROV,
  b.SNAME,
  b.SMOBILEPHONE,
  b.SELLERID,
  '1',
  '1')
求找错！~~~~~~~

------解决方案--------------------
按照楼主提供的建表与merge语句，我在oracle库上进行了测试，merge语句可以正常执行，没有语法上的错误。如果是语句运行的结果不符合期望目标的情况，请楼主详细说明表中的相关数据及期望目标。