SQL Days before end of the month - sql

Question

i have got table with transactions, looking like:
+----+--------------+----------------+------+
| ID | OrderDate | DeliveryDate | EUR |
+----+--------------+----------------+------+
| 1 | 2015-02-21 | 2015-02-25 | 100 |
| 2 | 2015-03-01 | 2015-03-14 | 110 |
| 3 | 2015-03-01 | 2015-03-17 | 90 |
| 4 | 2015-03-10 | 2015-03-20 | 250 |
| 5 | 2015-03-31 | 2015-03-31 | 350 |
+----+--------------+----------------+------+
ANd I need to get sum of revenue and number of orders (COUNT of IDs) based on Days before the end of the month when order gets delivered.
SELECT datediff(day, OrderDate, CAST(DATEADD(month, DATEDIFF(month,0,getdate()+1,0)-1) as Date) as DBEOM, SUM(EUR) as Rev, COUNT(ID) as NumberOfOrders
FROM transactions
WHERE MONTH(DeliveryDate) = 3 AND YEAR(DeliveryDate) = 2015
GROUP BY datediff(day, OrderDate, CAST(DATEADD(month, DATEDIFF(month,0,getdate()+1,0)-1) as Date) as DBEOM
ORDER BY 1
The result in this case would be like:
+-----+-----+----------------+
|DBEOM| Rev | NumberOfOrders |
+-----+-----+----------------+
| 0 | 350 | 1 |
| 21 | 250 | 1 |
| 30 | 200 | 2 |
+-----+-----+----------------+
This is done in SQL 2008, so I can't simply use EOMONTH. I have tried, what is above, but i am getting
ERROR -
[Microsoft][ODBC SQL Server Driver][SQL Server]The datediff function
requires 3 argument(s).
Many thanks in advance for advice!

Answer 1

The easiest way I've found get the last day of the month with more primitive functions is to get the first day of the next month and then subtract a day.
I'm not a TSQL guy so this syntax likely won't be correct but you need something more like
DATEADD(day, DATEFROMPARTS(DATEPART(year, DATEADD(month,1,getdate()), DATEPART(month, DATEADD(month,1,getdate()), 1), -1)

Answer 2

Try:
SELECT datediff(day,
OrderDate,
dateadd(DAY,
-1,
dateadd(MONTH,
1,
dateadd(DAY,
1-day(DeliveryDate),
DeliveryDate
)
)
)
) as DBEOM, SUM(EUR) as Rev, COUNT(ID) as NumberOfOrders
FROM t
WHERE MONTH(DeliveryDate) = 3 AND YEAR(DeliveryDate) = 2015
GROUP BY datediff(day,
OrderDate,
dateadd(DAY,
-1,
dateadd(MONTH,
1,
dateadd(DAY,
1-day(DeliveryDate),
DeliveryDate
)
)
)
)
ORDER BY 1
sqlfiddle.com