插入一条记录但不覆盖原记录

[zhangle861010]

例如：
a表 id ps wd
1 we er
2 re
3 er
4 23
5 ty
b表 id1 ps1 wd1
2 23
3 67
4 er
5 89


我想插入b 表中的纪录插入a表！

a id ps wd
1 we er
2 23 re
3 67 er
4 23 er
5 89 ty

[bing0804]

insert into a
select id1,ps1,wd1 form b
where id1 not in(select id from a) and ps1 not in(select ps from a)
and wd1 not in(select wd from a)

[pt1314917]

update a set ps=ps1 from a,b where id=id1 and isnull(ps,'')=''
update a set wd=wd1 from a,b where id=id1 and isnull(wd,'')=''

[-狙击手-]

update A
set ps = case when isnull(ps,'') = '' then b.ps1 else ps end,
    wd = case when isnull(wd,'') = '' then b.wd1 else wd end
from a ,b 
where a.id = b.id