Find a persons closing ratio - sql-server

Question

I have staff members that are assigned tasks, I need to find the percentage of tasks that a staff member has completed year-to-date... of those that were assigned to him. If John is assigned 10 tasks, and completed 5 I need to show John has closed .50 (50%).
I have two tables:
Tasks and Tasks_cstm
Tasks t
| ID | STATUS |Date_Completed|
The statuses are 'In Progress', 'Not Started', 'Completed'
Tasks_cst tc
| ID_C|Staff_Member|
The tables are joined on t.id = tc.id_c
This returns the number completed:
(select count(*)as Completed from tasks_CSTM tc
join tasks t
on t.id = tc.id_c
where status = 'completed'
group by staff_member_C )
This returns the total number of tasks:
(select count(*)as Total from tasks_CSTM tc
join tasks t
on t.id = tc.id_c
group by staff_member_C )
This is what I've come up with, but it errors: Subquery returned more than 1 value.
select staff_member_c,((select count(*)as Completed from tasks_CSTM tc
join tasks t
on t.id = tc.id_c
where status = 'completed'
group by staff_member_C )/(select count(*)as Total from tasks_CSTM tc
join tasks t
on t.id = tc.id_c
group by staff_member_C ))
from tasks t
join tasks_CSTM tc
on t.id = tc.id_C
group by staff_member_C
Any help is appreciated.

Answer 1

Something like this I think:
select staff_member_c, sum(case when status='completed' then 1.0 end)/count(*) as pctCompleted
from tasks_cstm tc
join tasks t
on t.id = tc.id_c
group by staff_member_c
You might need "else 0.0" in the case statement (but don't in MSSQL), and you might need nullif(count(*),0) in the denominator (but probably not in any DBMS).

Answer 2

There's a couple issues here to grapple with. One of which is dealing with the "year-to-date" part. Right now, with a Date_Completed column, there's no way to know when a task was assigned/created, which invalidates our ability to know year-to-date info. Barring that part of the question, here's my query which should work. I have a WHERE clause commented out which can easily be adapted to use a Date_Assigned column for year-to-date info.
select
staff_member
, sum(case t.status when 'Completed' then 1.0 else 0 end) [Completed]
, count(*) [Total]
, sum(case t.status when 'Completed' then 1.0 else 0 end) / count(*) [CompletedPercent]
from
tasks t
inner join tasks_cstm tc
on t.id = tc.id_C
--where
-- dateadd(year, datediff(year, 0, Date_Assigned), 0) = dateadd(year, datediff(year, 0, getdate()), 0)
group by
staff_member
And here's the setup code I used to (un-comprehensibly) test it out:
create table tasks (ID int, Status varchar(50), Date_Completed date)
create table tasks_cstm (ID_C int, Staff_Member varchar(50))
insert into tasks
select 1, 'Not Started', null
union all
select 2, 'Completed', '2011-04-15'
union all
select 3, 'In Progress', null
insert into tasks_cstm
select 1, 'Cadaeic'
union all
select 2, 'Cadaeic'
union all
select 3, 'Cadaeic'
Resulting in this:
staff_member Completed Total CompletedPercent
------------------- -------------------- ----------- -----------------------
Cadaeic 1.0 3 0.333333

Answer 3

-- Tasks
declare #T table(ID int, Status varchar(20))
-- Tasks_cst
declare #TC table(ID_C int, Staff_Member varchar(20))
insert into #TC values (1, 'Staff 1')
insert into #TC values (2, 'Staff 2')
insert into #TC values (3, 'Staff 3')
insert into #T values (1, 'Completed')
insert into #T values (1, 'Completed')
insert into #T values (1, 'In Progress')
insert into #T values (2, 'Completed')
insert into #T values (2, 'In Progress')
insert into #T values (3, 'In Progress')
select *
from #TC as TC
cross apply
(select sum(case T.Status when 'Completed' then 1.0 else 0.0 end) / count(*)
from #T as T
where T.ID = TC.ID_C) as C(PrecentCompleted)
Result
ID_C Staff_Member PrecentCompleted
----------- -------------------- ---------------------------------------
1 Staff 1 0.666666
2 Staff 2 0.500000
3 Staff 3 0.000000