Trouble running a complex query in sql? - sql

Question

I am pretty new to SQL Server and just started playing with it. I am trying to create a table that shows attendance percentage by department.
So first i run this query:
SELECT CrewDesc, COUNT(*)
FROM database.emp
INNER JOIN database.crew on sim1 = sim2
GROUP BY CrewDesc
This gives a table like this:
Accounting 10
Marketing 5
Economics 20
Engineering 5
Machinery 5
Tech Support 10
Then i run another query:
SELECT DeptDescription, COUNT(*)
FROM database.Attendee
GROUP BY DeptDescription
This gives me the result of all the people that have attended meeting something like
Accounting 8
Marketing 5
Economics 15
Engineering 10
Tech Support 8
Then I get the current week in the year by SELECT Datepart(ww, GetDate()) as CurrentWeek To make this example easy lets assume this will be week "2".
Now the way i was going to create this was a table for each step but that seems like waste. Is there a way we can combine to tables in a query? So in the end result i would like a table like this
Total# Attd Week (Total*Week) Attd/(Total*week)%
Accounting 10 8 2 20 8/20
Marketing 5 5 2 10 5/10
Economics 20 15 2 40 15/40
Engineering 5 10 2 10 10/10
Machinery 5 NULL 2 10 0/10
Tech Support 10 8 2 20 8/20

Answer 1

Ok, note that my recommendation below is based on your exact existing queries - there are certainly other ways to construct this that may be more performant, but functionally this should work for your requirement. Also, it illustrates the key features of different join types that happen to be relevant for your request, as well as inline views (aka nested queries), which are a super-powerful technique in the SQL language as a whole.
select t1.CrewDesc, t1.Total, t2.Attd, t3.Week,
(t1.Total*t3.Week) as Total_x_Week,
case when isnull(t1.Total*t3.Week, 0) = 0 then 0 else isnull(t2.Attd, 0) / isnull(t1.Total*t3.Week, 0) end as PercentageAttd
from (
SELECT CrewDesc, COUNT(*) AS Total
FROM database.emp INNER JOIN database.crew on sim1 = sim2
GROUP BY CrewDesc
) t1
left outer join /* left outer to keep all rows from t1 */ (
SELECT DeptDescription, COUNT(*) AS Attd
FROM database.Attendee GROUP BY DeptDescription
) t2
on t1.CrewDesc = t2.DeptDescription
cross join /* useful when adding a scalar value to all rows */ (
SELECT Datepart(ww, GetDate()) as Week
) t3
order by t1.CrewDesc
Good luck!

Answer 2

Try something like this
SELECT COALESCE(a.crewdesc,b.deptdescription),
a.total,
b.attd,
Datepart(ww, Getdate()) AS week,
total * Datepart(ww, Getdate()),
b.attd/(a.total*Datepart(ww, Getdate()))
FROM (query 1) a
FULL OUTER JOIN (query 2) b
ON a.crewdesc = b.deptdescription

Answer 3

WITH Total AS ( SELECT CrewDesc, COUNT(*) AS [Count]
FROM database.emp
INNER JOIN database.crew on sim1 = sim2
GROUP BY CrewDesc
),
Attd AS ( SELECT DeptDescription, COUNT(*) AS [Count]
FROM database.Attendee
GROUP BY DeptDescription
)
SELECT COALESCE(CrewDesc,DeptDescription) AS [Dept],
Total.[Count] AS [Total#],Attd.[Count] AS [Attd],
Total.[Count] * Datepart(ww, GetDate()) AS [(Total*Week)],
CAST(Attd.[Count] AS VARCHAR(10))+'/'+ CAST((Total.[Count] * Datepart(ww, GetDate()))AS VARCHAR(10)) AS [Attd/(Total*week)%]
FROM Total INNER JOIN Attd ON Total.CrewDesc = Attd.DeptDescription

Answer 4

I'm assuming your queries are correct -- you give no real information about your model so I've no way to know. They look wrong since the same data is called CrewDesc in one table and Dept in another. Also the join sim1 = sim2 seems very strange to me. In any case given the queries you posted this will work.
With TAttend as
(
SELECT CrewDesc, COUNT(*) as TotalNum
FROM database.emp
INNER JOIN database.crew on sim1 = sim2
GROUP BY CrewDesc
), Attend as
(
SELECT DeptDescription, COUNT(*) as Attd
FROM database.Attendee
GROUP BY DeptDescription
)
SELECT CrewDesc as Dept, TotalNum, ISNULL(Attd, 0) as Attd ,Datepart(ww, GetDate()) as Week,
CASE WHEN ISNULL(Attd, 0) > 0 THEN 0
ELSE ISNULL(Attd, 0) / (TotalNum * Datepart(ww, GetDate()) ) END AS Percent
FROM TAttend
LEFT JOIN Attend on CrewDesc = DeptDescription