求教大神，SQL这个怎么两个栏位的数据同时存在另一个表

[jx-lpcx]

列如表a有station和cause两个栏位的数据，我想在表b中判断表a的station和cause两个栏位的数据都存在，不存在的写到表b中，谢谢啦

[文盲老顾]

insert into b(字段名)
select val 
from (
	select * 
	from a
	unpivot(val for col in (station,cause)) p
) a
where not exists(select top 1 1 from b where 字段名=a.val)

两个帖子都结贴吧

[唐诗三百首]

insert into 表b(station,cause)
 select a.station,a.cause
 from 表a a
 left join 表b b
    on a.station=b.station
	   and a.cause=b.cause
 where b.station is null

[锟斤拷锟斤拷]

MERGE INTO b target 
USING a source
ON (target.station=source.station AND target.cause =source.cause ) 
WHEN NOT MATCHED THEN 
    INSERT (station,cause) VALUES (source.station,source.cause );

[morliz子轩]

引用 楼主 tianxia978 的回复:

列如表a有station和cause两个栏位的数据，我想在表b中判断表a的station和cause两个栏位的数据都存在，不存在的写到表b中，谢谢啦

if not exists(select 1 from syscolumns inner join sysobjects on sysobjects.id = syscolumns.id
    where syscolumns.name = 'station' and syscolumns.name = 'cause' and sysobject.name = "B表'
begin
      update B ……

end