tsql month problem - sql

Question

I have a table like:
id month cost
------------------
1 Jan 200
1 Mar 204
1 May 200
1 Dec 201
I need an output like( order by month including the other months of a year-displaying all 12 months):
to month cost
------------------
1 Jan 200
NULL Feb NULL
1 Mar 204
....
....
....
1 Dec 201
any idea or solution how to do this in TSQL?
Thanks!
edit:: month is extracted from a datetime value.
in real world i'll have to show previous 12 months from last month in a DESC order! any suggestion for that?

Answer 1

Try building a reference table of months, and JOINing on it. It's the quickest way to do this with months in varchar datatype.
declare #foo table (id int, [mon] varchar(100), cost int)
declare #mon table (mon varchar(100), orderWeight int)
INSERT INTO #mon (mon, orderWeight)
VALUES ('Jan',1), ('Feb',2),('Mar',3),('Apr',4),('May',5),('Jun',6),('Jul',7),
('Aug',8),('Sep',9),('Oct',10),('Nov',11),('Dec',12)
INSERT INTO #foo(id, [mon], cost)
VALUES ( 1 ,'Jan' , 200),
( 1 ,'Mar', 204),
( 1 ,'May' , 200),
( 1 ,'Dec' , 201)
select f.id,
m.[mon] ,
f.cost
from #mon as m
left join #foo as f on m.mon = f.mon
order by m.orderWeight
Results:
Your ordering will now be guaranteed with the order by orderWeight.

Answer 2

Sample table
create table mytable(id int, dt datetime, cost money)
insert mytable values
(1,GETDATE()-10,200),
(1,GETDATE()-40,204),
(1,GETDATE()-100,200),
(1,GETDATE()-200,201);
The query, using SQL Server 2008 specific syntax, and sorted properly
select
t.id [to],
CONVERT(char(3),dateadd(month,-M.N,L.PVT),7) [Month],
sum(t.cost) totalCost
from (select PVT=dateadd(month,datediff(month,0,getdate())-1,0)) L
cross join (values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11)) M(N)
left join mytable t
on t.dt >= dateadd(month,-M.N,L.PVT)
and t.dt < dateadd(month,-M.N+1,L.PVT)
group by t.id, right(CONVERT(char(9),dt,6),6), M.N, L.PVT
order by M.N
What it does:
right(CONVERT(char(9),dt,6),6) converts a date into the format 'DD MMM YY', we only need the MMM YY part
In the SELECT, we further extract only the 3-char month from it, using LEFT( , 3)
The subquery L has a single record and column, PVT, which is the first date of the last month
The number series 0-11 is used to create the month values for the last 12 months, using the formula dateadd(month,-M.N,L.PVT)
The range t.dt >= .. and t.dt < .. finds data for a single month

Answer 3

How about this?
The result contains month and year, but you can strip it as you want.
;with months
as
(
select dateadd(month, -1, dateadd(day, datediff(day, 0, getdate()), 0)) as m
union all
select dateadd(month, -1, m)
from months
where m > dateadd(month, -12, getdate())
)
-- Testdata
,yourTable(id,somedate,cost)
as
(
select 1, '2011-01-03', 200
union all
select 1, '2011-03-06', 204
union all
select 1, '2010-05-09', 200
union all
select 1, '2010-05-19', 201
union all
select 1, '2010-12-02', 201
)
-- end testdata
select yt.id
,datename(month,coalesce(yt.somedate, m.m)) as [month]
,datename(year,coalesce(yt.somedate, m.m)) as [year]
--,yt.cost
,sum(yt.cost) as cost
from months m
left join yourTable yt
on datepart(year, yt.someDate) = DATEPART(year, m.m)
and datepart(month, yt.someDate) = DATEPART(month, m.m)
group by
yt.id
,datename(month,coalesce(yt.somedate, m.m))
,datename(year,coalesce(yt.somedate, m.m))
,m.m
order by m.m desc
Edit: Altered solution to support sum.
Remove the group by-section and alter the comment of cost, to get the old solution.