Creating Columns for Summed Answers - sql

Question

So I'm trying to move my row info into the column - I haven't used a Pivot before and tried using it now but clearly I'm doing something wrong -.-;
Here is my original Query
(Select
CASE WHEN ee.ExpenseTypeID=1 THEN Sum(Amount)
WHEN ee.ExpenseTypeID=2 THEN Sum(Amount)
WHEN ee.ExpenseTypeID=3 THEN Sum(Amount)
WHEN ee.ExpenseTypeID=4 THEN Sum(Amount) END as Amount,
et.ExpenseDescription,
ee.UserID
From ExpensesEntries ee, ExpenseTypes et
Where ee.ExpenseTypeID=et.ExpenseTypeID
Group By ee.ExpenseTypeID, et.ExpenseDescription, ee.UserID
Order By UserID) b
Which produces something like this
Amount | ExpenseDescription | UserID
----------------------------------------
156.00 | Upload | 123
----------------------------------------
23.00 | Parking | 123
----------------------------------------
15.37 | Other | 123
----------------------------------------
112.00 | Other | 456
----------------------------------------
28.50 | Parking | 456
----------------------------------------
What I would like to do
UserID | Upload | Parking | Other
----------------------------------
123 | 156.00 | 23.00 | 15.37
----------------------------------
456 | NULL | 28.50 | 112.00
I tried doing this - which is the equivalent of slapping on a Pivot but with the Cases in my original select - I'm not sure if I need to get rid of them entirely and add it into Pivot ?
Select
CASE WHEN ee.ExpenseTypeID=1 THEN Sum(Amount)
WHEN ee.ExpenseTypeID=2 THEN Sum(Amount)
WHEN ee.ExpenseTypeID=3 THEN Sum(Amount)
WHEN ee.ExpenseTypeID=4 THEN Sum(Amount) END as Amount,
et.ExpenseDescription,
ee.UserID
From ExpensesEntries ee, ExpenseTypes et
Where ee.ExpenseTypeID=et.ExpenseTypeID
Group By ee.ExpenseTypeID, et.ExpenseDescription, ee.UserID
Order By UserID
PIVOT
(Amount
FOR et.ExpenseDescription IN ('Upload','Other','Parking')
) as pvt

Answer 1

You didn't provide details on what each of the ExpenseTypeId values relate to but you can do this using an aggregate function with a CASE expression. The CASE expression will check the value of the ExpenseTypeId and get a sum of the amount - you will then name the column with the ExpenseDescription:
select ee.UserId,
sum(case when ee.ExpenseTypeID=1 then Amount else 0 end) Upload,
sum(case when ee.ExpenseTypeID=2 then Amount else 0 end) Parking,
sum(case when ee.ExpenseTypeID=3 then Amount else 0 end) Other
from ExpensesEntries ee
inner join ExpenseTypes et
on ee.ExpenseTypeID=et.ExpenseTypeID
group by ee.UserId;
If you want to use PIVOT, then you would alter your query to something similar to the following. This uses a join between your 2 tables in a subquery and you return the UserId, ExpenseDescription and Amount. The PIVOT will sum the amount for each ExpenseDescription - this process converts the descriptions to columns:
select UserId, Upload, Other, Parking
from
(
select ee.UserId,
et.ExpenseDescription
Amount
from ExpensesEntries ee
inner join ExpenseTypes et
on ee.ExpenseTypeID=et.ExpenseTypeID
) d
pivot
(
sum(Amount)
for ExpenseDescription in (Upload, Other, Parking)
) p;