开发过程遇到 两张表字段相同，但是需要将旧表数据插入新表，如果新表已有此数据则不予插入。

第一种方法
select * from TA_TRL_GO_COMEBILL A left join (
         SELECT S_BOOKORGCODE,S_MSGID,S_BNKNO
           FROM TA_TRL_HVPS_COMEBILL
) B on a.S_BNKNO = b.S_BNKNO and a.S_MSGID = b.S_MSGID where b.S_MSGID is null

第二种方法
merge into TA_TRL_GO_COMEBILL as a
using (
    SELECT S_BOOKORGCODE,S_MSGID,S_BNKNO FROM TA_TRL_HVPS_COMEBILL  
      where  S_PAYERNAME like '%财政%'  ) as b
       on a.S_BNKNO = b.S_BNKNO and a.S_MSGID = b.S_MSGID
WHEN NOT MATCHED THEN
      INSERT (S_BOOKORGCODE,S_MSGID,S_BNKNO)
              VALUES (b.S_BOOKORGCODE,b.S_MSGID,b.S_BNKNO)