从一个表中查找某两个字段重复的记录，把所有重复记录插入到另一表中。
sql代码如下：
insert into t1 select * from wood where rtrim(reason)+rtrim(CONVERT(char(20), dup_id)) in
(select rtrim(a.reason)+rtrim(CONVERT(char(20), a.dup_id))
from
(select reason, dup_id from wood group by reason, dup_id having count(*)>1) a)
