I have a Monthly Status database view I need to build a report based on. The data in the view looks something like this:
Category | Revenue | Yearh | Month
B
@Christian -- markdown editor -- UGH; especially when the preview and the final version of your post disagree... @Christian -- full outer join -- the full outer join is overruled by the fact that there are references to SP1 in the WHERE clause, and the WHERE clause is applied after the JOIN. To do a full outer join with filtering on one of the tables, you need to put your WHERE clause into a subquery, so the filtering happens before the join, or try to build all of your WHERE criteria onto the JOIN ON clause, which is insanely ugly. Well, there's actually no pretty way to do this one.
@Jonas: Considering this:
Also, the report is actually for financial year - so I would love to have empty columns with 0 in both if there was no sales in say month 5 for either 2007 or 2008.
and the fact that this job can't be done with a pretty query, I would definitely try to get the results you actually want. No point in having an ugly query and not even getting the exact data you actually want. ;)
So, I'd suggest doing this in 5 steps:
1. create a temp table in the format you want your results to match
2. populate it with twelve rows, with 1-12 in the month column
3. update the "This Year" column using your SP1 logic
4. update the "Last Year" column using your SP2 logic
5. select from the temp table
Of course, I guess I'm working from the assumption that you can create a stored procedure to accomplish this. You might technically be able to run this whole batch inline, but that kind of ugliness is very rarely seen. If you can't make an SP, I suggest you fall back on the full outer join via subquery, but it won't get you a row when a month had no sales either year.
The trick is to do a FULL JOIN, with ISNULL's to get the joined columns from either table. I usually wrap this into a view or derived table, otherwise you need to use ISNULL in the WHERE clause as well.
SELECT
Program,
Month,
ThisYearTotalRevenue,
PriorYearTotalRevenue
FROM (
SELECT
ISNULL(ThisYear.Program, PriorYear.Program) as Program,
ISNULL(ThisYear.Month, PriorYear.Month),
ISNULL(ThisYear.TotalRevenue, 0) as ThisYearTotalRevenue,
ISNULL(PriorYear.TotalRevenue, 0) as PriorYearTotalRevenue
FROM (
SELECT Program, Month, SUM(TotalRevenue) as TotalRevenue
FROM PVMonthlyStatusReport
WHERE Year = @FinancialYear
GROUP BY Program, Month
) as ThisYear
FULL OUTER JOIN (
SELECT Program, Month, SUM(TotalRevenue) as TotalRevenue
FROM PVMonthlyStatusReport
WHERE Year = (@FinancialYear - 1)
GROUP BY Program, Month
) as PriorYear ON
ThisYear.Program = PriorYear.Program
AND ThisYear.Month = PriorYear.Month
) as Revenue
WHERE
Program = 'Bikes'
ORDER BY
Month
That should get you your minimum requirements - rows with sales in either 2007 or 2008, or both. To get rows with no sales in either year, you just need to INNER JOIN to a 1-12 numbers table (you do have one of those, don't you?).
About the markdown - Yeah that is frustrating. The editor did preview my HTML table, but after posting it was gone - So had to remove all HTML formatting from the post...
@kcrumley I think we've reached similar conclusions. This query easily gets real ugly. I actually solved this before reading your answer, using a similar (but yet different approach). I have access to create stored procedures and functions on the reporting database. I created a Table Valued function accepting a product category and a financial year as the parameter. Based on that the function will populate a table containing 12 rows. The rows will be populated with data from the view if any sales available, if not the row will have 0 values.
I then join the two tables returned by the functions. Since I know all tables will have twelve roves it's allot easier, and I can join on Product Category and Month:
SELECT
SP1.Program,
SP1.Year,
SP1.Month,
SP1.TotalRevenue AS ThisYearRevenue,
SP2.TotalRevenue AS LastYearRevenue
FROM GetFinancialYear(@Category, 'First Look', 2008) AS SP1
RIGHT JOIN GetFinancialYear(@Category, 'First Look', 2007) AS SP2 ON
SP1.Program = SP2.Program AND
SP1.Month = SP2.Month
I think your approach is probably a little cleaner as the GetFinancialYear function is quite messy! But at least it works - which makes me happy for now ;)
The Case Statement is my best sql friend. You also need a table for time to generate your 0 rev in both months.
Assumptions are based on the availability of following tables:
sales: Category | Revenue | Yearh | Month
and
tm: Year | Month (populated with all dates required for reporting)
Example 1 without empty rows:
select
Category
,month
,SUM(CASE WHEN YEAR = 2008 THEN Revenue ELSE 0 END) this_year
,SUM(CASE WHEN YEAR = 2007 THEN Revenue ELSE 0 END) last_year
from
sales
where
year in (2008,2007)
group by
Category
,month
RETURNS:
Category | Month | Rev. This Year | Rev. Last Year
Bikes 1 10 000 0
Bikes 2 12 000 11 000
Bikes 3 12 000 11 500
Bikes 4 0 15 400
Example 2 with empty rows: I am going to use a sub query (but others may not) and will return an empty row for every product and year month combo.
select
fill.Category
,fill.month
,SUM(CASE WHEN YEAR = 2008 THEN Revenue ELSE 0 END) this_year
,SUM(CASE WHEN YEAR = 2007 THEN Revenue ELSE 0 END) last_year
from
sales
Right join (select distinct --try out left, right and cross joins to test results.
product
,year
,month
from
sales --this ideally would be from a products table
cross join tm
where
year in (2008,2007)) fill
where
fill.year in (2008,2007)
group by
fill.Category
,fill.month
RETURNS:
Category | Month | Rev. This Year | Rev. Last Year
Bikes 1 10 000 0
Bikes 2 12 000 11 000
Bikes 3 12 000 11 500
Bikes 4 0 15 400
Bikes 5 0 0
Bikes 6 0 0
Bikes 7 0 0
Bikes 8 0 0
Note that most reporting tools will do this crosstab or matrix functionality, and now that i think of it SQL Server 2005 has pivot syntax that will do this as well.
Here are some additional resources. CASE http://www.4guysfromrolla.com/webtech/102704-1.shtml SQL SERVER 2005 PIVOT http://msdn.microsoft.com/en-us/library/ms177410.aspx
Using pivot and Dynamic Sql we can achieve this result
SET NOCOUNT ON
IF OBJECT_ID('TEMPDB..#TEMP') IS NOT NULL
DROP TABLE #TEMP
;With cte(Category , Revenue , Yearh , [Month])
AS
(
SELECT 'Bikes', 10000, 2008,1 UNION ALL
SELECT 'Bikes', 12000, 2008,2 UNION ALL
SELECT 'Bikes', 12000, 2008,3 UNION ALL
SELECT 'Bikes', 15000, 2008,1 UNION ALL
SELECT 'Bikes', 11000, 2007,2 UNION ALL
SELECT 'Bikes', 11500, 2007,3 UNION ALL
SELECT 'Bikes', 15400, 2007,4
)
SELECT * INTO #Temp FROM cte
Declare @Column nvarchar(max),
@Column2 nvarchar(max),
@Sql nvarchar(max)
SELECT @Column=STUFF((SELECT DISTINCT ','+ 'ISNULL('+QUOTENAME(CAST(Yearh AS VArchar(10)))+','+'''0'''+')'+ 'AS '+ QUOTENAME(CAST(Yearh AS VArchar(10)))
FROM #Temp order by 1 desc FOR XML PATH ('')),1,1,'')
SELECT @Column2=STUFF((SELECT DISTINCT ','+ QUOTENAME(CAST(Yearh AS VArchar(10)))
FROM #Temp FOR XML PATH ('')),1,1,'')
SET @Sql= N'SELECT Category,[Month],'+ @Column +'FRom #Temp
PIVOT
(MIN(Revenue) FOR yearh IN ('+@Column2+')
) AS Pvt
'
EXEC(@Sql)
Print @Sql
Result
Category Month 2008 2007
----------------------------------
Bikes 1 10000 0
Bikes 2 12000 11000
Bikes 3 12000 11500
Bikes 4 0 15400
I could be wrong but shouldn't you be using a full outer join instead of just a left join? That way you will be getting 'empty' columns from both tables.
http://en.wikipedia.org/wiki/Join_(SQL)#Full_outer_join