Sql to update login id's dynamically based on count - sql

Question

I have 2 tables. One is main table and other one is login table. I may have 10 Records in Main table and 6 Records in login table. Each login id has to be assingned equally to main table. Can any one please give me the best solution to update the login information.
Example
Create table ##t1
(id int identity,
name varchar(5),
loginid varchar(10)
divno char(3))
create table ##l1
(
id int identity,
name varchar(10),divno char(3))
insert into ##t1 values
('Jin',null,'001')
insert into ##t1 values
('Anu',null,'001')
insert into ##t1 values
('kir',null'002')
insert into ##t1 values
('Asi',null,'003')
insert into ##t1 values
('Nil',null,'002')
insert into ##t1 values
('sup',null,'003')
insert into ##t1 values
('amu',null,'003')
insert into ##t1 values
('mani',null,'003')
insert into ##l1 values
('A','001')
insert into ##l1 values
('B','001')
insert into ##l1 values
('C','002')
insert into ##l1 values
('D','002')
insert into ##l1 values
('E','002')
insert into ##l1 values
('F','003')
Data Example
Main table
id name loginid divno
----------- ----- ----------
1 Jin NULL 001
2 Anu NULL 001
3 kir NULL 002
4 Asi NULL 003
5 Nil NULL 002
6 sup NULL 003
7 amu NULL 003
8 mani NULL 003
Login Table
id name divno
----------- -------------
1 A 001
2 B 001
3 C 002
4 D 002
5 E 002
6 F 003
desired output
How can we do this without looping?

Answer 1

update ##t1
set loginid = #l1.name
from
##t1
inner join
(select *, (ROW_NUMBER() Over (order by id) -1)% (select COUNT(*) from ##l1)+1 as rn from ##t1) v
on ##t1.id = v.id
inner join
##l1
on v.rn = ##l1.id

Answer 2

Let me do this as a select query rather than as an upadte.
select id, name, l.login
from (select mt.*,
(row_number() over (order by id) % l.loginCount) + 1 as loginSeqnum
from MainTable mt cross join
(select count(*) as loginCount from login) l
) mt join
(select l.*, row_number() over (order by id) as seqnum
from login l
) l
on mt.LoginSeqnum = l.seqnum
What this is doing is adding a sequence number to the logins (just in case loginid is not 1..n. It then calculates a similar value for each record in the first table.
One nice thing about this method is you can modify it to get more random orderings, by changing the "order by" clause in the row_number() statements. For instance, using "order by newid()" will randomize the assignment, rather than doing it in a round-robin fashion.