alter table 表 add newfield int identity(1,1)delete 表 where newfield not in( select min(newfield) from 表 group by 除newfield外的所有字段 )alter table 表 drop column newfield
CREATE TRIGGER 名1 ON 表 FOR INSERT AS if exists(select 1 from inserted tem where exists(select 1 from 表 where 列1=tem.列1 and 列2=tem.列2))
where newfield not in(
select min(newfield) from 表 group by 除newfield外的所有字段
)alter table 表 drop column newfield
FOR INSERT
AS
if exists(select 1 from inserted tem where exists(select 1 from 表 where 列1=tem.列1 and 列2=tem.列2))