SQL Query Problem - sql

Question

When I am doing SQL Query on the database then all the months that are there in database and all the values corresponding to that particular month will be summed up in the Amount Column.
Suppose this is a table
Month Category Amount Year
January Rent 12 2011
March Food 13 2011
January Gas 14 2011
May Enter 15 2011
March General 16 2011
So I written the query to sum all the values of a particular month by using this:-
"SELECT Month, SUM(Amount) AS OrderTotal FROM budget1 WHERE year="2011" GROUP BY month "
So I got the result as this:-
Month Amount
January 26
March 29
May 15
But I want is that it should show all the months from January to December and Value of 0 infront of those month which are not there in the database like this for above example.
Month Amount
January 26
February 0
March 29
April 0
May 15
June 0
July 0
August 0
September 0
October 0
November 0
December 0
Any help will be appreciated..!!

Answer 1

Create a table with all months Jan-Dec, call it Months. Just a single column with the names or add an extra integer for sort order (I usually call this the ordinal column), as follows:
create table months (
month varchar(20),
ordinal
);
insert into months values ('January', 1);
insert into months values ('February', 2);
insert into months values ('March', 3);
...
insert into months values ('December', 12);
The specific syntax may depend upon your database platform. Then, depending upon your database:
SELECT months.Month, SUM(Amount) AS OrderTotal
FROM months
left join budget1
on months.month = budget1.Month
WHERE year="2011" or year is null
GROUP BY months.month, months.ordinal
ORDER by month.ordinal
You'll need to convert SUM(Amount) to 0 when null. The specific function or approach to do this depends upon your database platform, or you can just do it in the code that is interpreting the results.

Answer 2

Build a month table, with your months and the sort order. Then left join your month column to the month column in your data table. That will get you the zeros.
So your table will look like
Month Sort
======================
January 1
February 2
March 3
etc.
You can create the table by using Create Table, following by Insert Scripts
CREATE TABLE #months (month VARCHAR(50), sort INT);
INSERT INTO #months VALUES ('January', 1);
INSERT INTO #months VALUES ('February', 2);
etc.
Then
SELECT m.Month, SUM(Amount) AS OrderTotal
FROM #months m LEFT OUTER JOIN budget1 on m.Month = budget1.Month
WHERE year=2011
GROUP BY m.Month
ORDER BY m.Sort