Get the Values with null for all dates

Question

hi,
 i have a scanrio to get the sales trend. The data look like below
CREATE TABLE #T1
( Item varchar(50),
SalesDate Date,
Quantity int
INSERT INTO #T1 VALUES ('Item1', '2013/02/01', 3)
INSERT INTO #T1 VALUES ('Item2', '2013/02/01', 5)
INSERT INTO #T1 VALUES ('Item1', '2013/02/02', 2)
INSERT INTO #T1 VALUES ('Item1', '2013/02/03', 6)
INSERT INTO #T1 VALUES ('Item2', '2013/02/03', 4)
SELECT * FROM #T1
Here i have 2 items sales details for 3 days. So user can get the sales trend by passing StartDate and EndDate as 2 parameters.  But it will return the existing date values only. In this example Item2 not have sales record in the table for '2013/02/02'
But needs to give null values in the select Query
My Existing Output
Item SalesDate Quantity
Item1 2013-02-01 3
Item2 2013-02-01 5
Item1 2013-02-02 2
Item1 2013-02-03 6
Item2 2013-02-03 4
My expected output is
Item SalesDate Quantity
Item1 2013-02-01 3
Item2 2013-02-01 5
Item1 2013-02-02 2
Item2 2013-02-02 null
Item1 2013-02-03 6
Item2 2013-02-03 4
Can you help to write the query. I wrote using CTE but if the ITem is single value its ok. But for multiple items how can i get the empty dates

Answer 1

akhil,
Check if this helps you:
--CREATE TABLE #T1
--( Item varchar(50),
-- SalesDate Datetime,
-- Quantity int
--INSERT INTO #T1 VALUES ('Item1', '2013/02/01', 3)
--INSERT INTO #T1 VALUES ('Item2', '2013/02/01', 5)
--INSERT INTO #T1 VALUES ('Item1', '2013/02/02', 2)
--INSERT INTO #T1 VALUES ('Item1', '2013/02/03', 6)
--INSERT INTO #T1 VALUES ('Item2', '2013/02/03', 4)
SELECT * FROM #T1
declare @tab TABLE(date_col datetime)
insert @tab select '2013/02/01'
insert @tab select '2013/02/02'
insert @tab select '2013/02/03'
;with cte
as
select * from
(select distinct Item from #t1) a
cross join
(select date_col from @tab) b
select c.item,c.date_col,t.Quantity from cte c
left join #T1 t on c.Item=t.item and c.date_col=t.SalesDate
You have the following options for the population of @tab (that decodes the dates for which values are to be obtained):
either explicitly as i have done
using a select statement on #T1 like, insert @tab select distinct SalesDate from #T1
or for past three days means, something like - getdate(),getdate()-1 and getdate()-2
Thanks,
Jay
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