T-Sql Distribute data into groups based on existing numbers

dreaddan101

Hi, i've been looking at moving one of our processed from excel (+vba) into t-sql to make life easier but am stuck. We have lots of tasks that are assigned to work groups which we want to distribute evenly across the work groups. This is a simple task for ntile.. However when these tasks are no longer required they are removed which leaves the groups uneven. When new tasks are added we want to still try to keep these groups balanced. EG Existing groups :

GroupName - Task Count
Group1 - 1000
Group2 - 999
Group3 - 998

If we were to add 6 new tasks they would have more assigned to Group 2 & 3 as they have less than group 1.

Task 1 - Group3
Task 2 - Group3
Task 3 -Group2
Task 4 - Group1
Task 5 - Group2
Task 6 - Group3

Sample tables

Create table GroupTable
(GroupID int, Name varchar(200) )
Insert into GroupTable values (1,'Group1')
Insert into GroupTable values (2,'Group2')
Insert into GroupTable values (3,'Group3')

Create table Jobs(jobid int identity(1,1), name varchar(100),Groupid int)
--Existing tasks
Insert into Jobs(name,Groupid) values ('Task1',1)
Insert into Jobs(name,Groupid) values ('Task2',1)
Insert into Jobs(name,Groupid) values ('Task3',1)
Insert into Jobs(name,Groupid) values ('Task4',1)
Insert into Jobs(name,Groupid) values ('Task5',2)
Insert into Jobs(name,Groupid) values ('Task6',2)
Insert into Jobs(name,Groupid) values ('Task6',2)
Insert into Jobs(name,Groupid) values ('Task7',3)

-- New tasks
Insert into Jobs(name) values ('TaskA')
Insert into Jobs(name) values ('TaskB')
Insert into Jobs(name) values ('TaskC')
Insert into Jobs(name) values ('TaskD')
Insert into Jobs(name) values ('TaskE')
Insert into Jobs(name) values ('TaskF')

This gives us 6 unassigned tasks and a uneven group assignment

GROUPNAME TASK_COUNT
6
Group1 4
Group2 3
Group3 2

This means the new tasks will be assigned like this

TaskA - Group3
TaskB - Group3
TaskC - Group2
TaskD - Group1
TaskE - Group2
TaskF - Group3

Can anyone help? Thanks Dan

Jorgen Andersson

Insert new tasks like this:

insert into jobs
select top(1)
@TaskName,
groupid
from jobs
group by groupid
order by count(*),groupid

Wrong is evil and must be defeated. - Jeff Ello[^]