TSQL Multiple count using same table with different JOIN - sql

Question

I have a weird situation and not too sure how to approach it.
I have 2 separate tables:
Table A is submissions
id
submitterQID
nomineeQID
story
Table B is employees
QID
Name
Department
I am trying to get the total number of submissions grouped by department as well as the total number of nominations.
This is what my Stored procedure looks like:
BEGIN
SELECT TOP 50 count(A.[nomineeQID]) AS totalNominations,
count(A.[subQID]) AS totalSubmissions,
B.[DepartmentDesc] AS department
FROM empowermentSubmissions AS A
JOIN empTable AS B
ON B.[qid] = A.[nomineeQID]
WHERE A.[statusID] = 3
AND A.[locationID] = #locale
GROUP BY B.[Department]
ORDER BY totalNominations DESC
FOR XML PATH ('data'), TYPE, ELEMENTS, ROOT ('root');
END
This issue with this is that the JOIN is joining by the nomineeQID only and not the subQID as well.
My end result I am looking for is:
Department Customer Service has 25 submissions and 90 nominations
ORDERED BY the SUM of both counts...
I tried to just JOIN again on the subQID but was told I cant join on the same table twice.
Is there an easier way to accomplish this?

Answer 1

This is a situaton where you'll need to gather your counts independently of each other. Using two left joins will cause some rows to be counted twice in the first left join when the join condition is met for both. Your scenario can be solved using either correlated subqueries or an outer apply gathering the counts on different criteria. I did not present a COUNT(CASE ... ) option here, because you don't have an either-or scenario in the data, you have two foreign keys to the employees table. So, setting up sample data:
declare #empowermentSubmissions table (submissionID int primary key identity(1,1), submissionDate datetime, nomineeQID INT, submitterQID INT, statusID INT, locationID INT)
declare #empTable table (QID int primary key identity(1,1), AreaDesc varchar(10), DepartmentDesc varchar(20))
declare #locale INT = 0
declare #n int = 1
while #n < 50
begin
insert into #empTable (AreaDesc, DepartmentDesc) values ('Area ' + cast((#n % 2)+1 as varchar(1)), 'Department ' + cast((#n % 4)+1 as varchar(1)))
set #n = #n + 1
end
set #n = 1
while #n < 500
begin
insert into #empowermentSubmissions (submissionDate, nomineeQID, submitterQID, StatusID, locationID) values (dateadd(dd,-(cast(rand()*600 as int)),getdate()), (select top 1 QID from #empTable order by newid()), (select top 1 QID from #empTable order by newid()), 3 + (#n % 2) - (#n % 3), (#n % 2) )
set #n = #n + 1
end
And now the OUTER APPLY option:
SELECT TOP 50 E.DepartmentDesc, SUM(N.Nominations) Nominations, SUM(S.TotalSubmissions) TotalSubmissions
FROM #empTable E
OUTER APPLY (
SELECT COUNT(submissionID) Nominations
FROM #empowermentSubmissions A
WHERE A.statusID = 3
AND A.nomineeQID = E.QID
AND A.locationID = #locale
) N
OUTER APPLY (
SELECT COUNT(submissionID) TotalSubmissions
FROM #empowermentSubmissions A
WHERE A.statusID = 3
AND A.submitterQID = E.QID
AND A.locationID = #locale
) S
GROUP BY E.DepartmentDesc
ORDER BY SUM(Nominations) + SUM(TotalSubmissions) DESC