Update table gives primary key violation error - sql-server

Question

I have following tow tables
create table #temp(id int,rid int)
insert into #temp
select 1,1
union all
select 2,1
union all
select 3,1
select * from #temp
drop table #temp1
create table #temp1(id int, nid int,PRIMARY KEY CLUSTERED
(
id asc,nid asc
))
insert into #temp1
select 1,10
union all
select 2,10
union all
select 2,11
union all
select 3,10
Following are the both result sets:
id rid
1 1
2 1
3 1
id nid
1 10
2 10
2 11
3 10
I want to update #temp1 table with value from rid field of #temp table by matching id field from both tables. See following query:
select a.*
from #temp1 a inner join #temp b
on a.id = b.id
where a.id <> b.rid
It returns:
id nid
2 10
2 11
3 10
I want to update id with following query:
update a
set a.id = b.rid
-- select a.*
from #temp1 a inner join #temp b
on a.id = b.id
where a.id <> b.rid
But it returns
primary key violation error because of primary key in table #temp1.
I would like to delete the value if it is already exist if not then I would like to update
for example
id nid
1 10
2 10-- want to update but not able to this bcoz it violates primary key so delete this row.
2 11-- able to update this row but other 2 rows causing an issue.
3 10-- want to update but not able to this bcoz it violates primary key so delete this row.
Please suggest other ways to do this.

Answer 1

Because You are Violating the Primary Key Constraints
Check Below Tables
select B.*
from #temp1 a inner join #temp b
on a.id = b.id
where a.id <> b.rid
id rid
2 1
2 1
3 1
select * from #temp1
id nid
1 10
2 10
2 11
3 10
You are setting ID of above first table using join from #temp which already in #temp1
You Are attempt to Update Values which are already in #temp1 where id=2,2,3

Answer 2

select *
from #temp1 a inner join #temp b
on a.id = b.id
where a.id <> b.rid
You would be updating two id 2 records to the same value. You cannot do this, period. There is no other method to fix this except to drop the PK which I would suggest would be bad idea.
It is possible you need some further definition in your pdate to specify which of multiple records you want to update or you may need to delete the record which might end up as a duplicate before you do the update. Not knowing the business rules for what you are actually trying to accomplish or what your data means, it is impossiblet say what you can do to solve your problem. This ia case where the solution is dependant on the meaning and of course we have no meaning here.