Echilon Echilon - 4 months ago 17
SQL Question

SQL Server Group By Month

I have a table which has this schema

ItemID UserID Year IsPaid PaymentDate Amount
1 1 2009 0 2009-11-01 300
2 1 2009 0 2009-12-01 342
3 1 2010 0 2010-01-01 243
4 1 2010 0 2010-02-01 2543
5 1 2010 0 2010-03-01 475


I'm trying to get a query working which shows the totals for each month. So far I've tried DateDiff and nested selects, but neither gives me what I want. This is the closest I have I think:

DECLARE @start [datetime] = 2010/4/1;
SELECT ItemID, IsPaid,
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 And DateDiff(m, PaymentDate, @start) = 0 AND UserID = 100) AS "Apr",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =1 AND UserID = 100) AS "May",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =2 AND UserID = 100) AS "Jun",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =3 AND UserID = 100) AS "Jul",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =4 AND UserID = 100) AS "Aug",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =5 AND UserID = 100) AS "Sep",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =6 AND UserID = 100) AS "Oct",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =7 AND UserID = 100) AS "Nov",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =8 AND UserID = 100) AS "Dec",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =9 AND UserID = 100) AS "Jan",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =10 AND UserID = 100) AS "Feb",
(SELECT SUM(Amount) FROM Payments WHERE Year = 2010 AND DateDiff(m, PaymentDate, @start) =11 AND UserID = 100) AS "Mar"
FROM LIVE L INNER JOIN Payments I ON I.LiveID = L.RECORD_KEY
WHERE UserID = 16178


But I just get nulls when I should be getting values. Am I missing something?

Answer
SELECT CONVERT(NVARCHAR(10), PaymentDate, 120) [Month], SUM(Amount) [TotalAmount]
FROM Payments
GROUP BY CONVERT(NVARCHAR(10), PaymentDate, 120)
ORDER BY [Month]

You could also try:

SELECT DATEPART(Year, PaymentDate) Year, DATEPART(Month, PaymentDate) Month, SUM(Amount) [TotalAmount]
FROM Payments
GROUP BY DATEPART(Year, PaymentDate), DATEPART(Month, PaymentDate)
ORDER BY Year, Month