sql server - Handling non existent values in sql query expression for ssrs chart

Question

I am using the following query in an ssrs line chart. It counts how many orders are recorded each month based on each order date.

My problem is that when a month has no orders, rather than saying zero or null it removes the row for that month all together. I would prefer for it to count it as zero but null would be ok too.

Basically, I want to always have twelve rows whether they contain information or not.

How can I fix this? Is there an expression I can use or something? Or am I missing something completely obvious?

SELECT
MONTH(Ord.OrdDate) AS 'MONTH',
COUNT(CASE WHEN @Worker_ID1 IS NULL OR @Worker_ID1 = Worker.ID THEN 1 END) AS 'Worker1',
COUNT(CASE WHEN @Worker_ID2 IS NULL OR @Worker_ID2 = Worker.ID THEN 1 END) AS 'Worker2',
COUNT(CASE WHEN @Worker_ID3 IS NULL OR @Worker_ID3 = Worker.ID THEN 1 END) AS 'Worker3',
COUNT(CASE WHEN @Worker_ID4 IS NULL OR @Worker_ID4 = Worker.ID THEN 1 END) AS 'Worker4',
COUNT(CASE WHEN @Worker_ID5 IS NULL OR @Worker_ID5 = Worker.ID THEN 1 END) AS 'Worker5'

FROM Ord
JOIN Prod ON Ord.Prod_ID = Prod.ID
JOIN ProdType ON Prod.ProdType_ID = ProdType.ID
JOIN Grouping ON Ord.Grouping_ID = Grouping.ID
JOIN Worker ON Grouping.Worker_ID = Worker.ID

WHERE @Year = YEAR(Ord.OrdDate)
AND (@ProdType_ID IS NULL OR @ProdType_ID = ProdType.ID)

GROUP BY MONTH(Ord.OrdDate)

Answer 1

As the above answers mentioned, you will need an outer join and some kind of calendar table. This is untested, but I think will work for you:

with dateCTE as
(
     select cast('2012-01-01' as datetime) dateValue -- start date
     union all
     select DateAdd(mm, 1, dateValue)
     from    dateCTE   
     where   dateValue < '2012-12-30' -- end date
 )
SELECT
MONTH(dateCTE.dateValue) AS 'MONTH',
COUNT(CASE WHEN @Worker_ID1 IS NULL OR @Worker_ID1 = Worker.ID THEN 1 END) AS 'Worker1',
COUNT(CASE WHEN @Worker_ID2 IS NULL OR @Worker_ID2 = Worker.ID THEN 1 END) AS 'Worker2',
COUNT(CASE WHEN @Worker_ID3 IS NULL OR @Worker_ID3 = Worker.ID THEN 1 END) AS 'Worker3',
COUNT(CASE WHEN @Worker_ID4 IS NULL OR @Worker_ID4 = Worker.ID THEN 1 END) AS 'Worker4',
COUNT(CASE WHEN @Worker_ID5 IS NULL OR @Worker_ID5 = Worker.ID THEN 1 END) AS 'Worker5'

FROM dateCTE
LEFT JOIN Ord on MONTH(dateCTE.datevalue) = MONTH(Ord.OrdDate)
JOIN Prod ON Ord.Prod_ID = Prod.ID
JOIN ProdType ON Prod.ProdType_ID = ProdType.ID
JOIN Groupord ON Ord.Groupord_ID = Groupord.ID
JOIN Worker ON Groupord.Worker_ID = Worker.ID

WHERE (@Year = YEAR(Ord.OrdDate) or ORD.prod_id is null)
AND (@DrugType_ID IS NULL OR @ProdType_ID = ProdType.ID)

GROUP BY MONTH(dateCTE.dateValue)
OPTION  (MAXRECURSION 0)