Question

I have some data on my table like:

DAY      | QTY | Name
1/1/2010 |  1  | jack
5/1/2010 |  5  | jack
2/1/2010 |  3  | wendy
5/1/2010 |  2  | wendy

my goal is to have a SP requesting a period of time (example: ‘2010-1-1’ to ‘2010-1-5’), and get no gaps.
Output example:

DAY      | QTY | Name
1/1/2010 |  1  | jack
2/1/2010 |  0  | jack
3/1/2010 |  0  | jack
4/1/2010 |  0  | jack
5/1/2010 |  5  | jack
1/1/2010 |  3  | wendy
2/1/2010 |  0  | wendy
3/1/2010 |  0  | wendy
4/1/2010 |  2  | wendy
5/1/2010 |  0  | wendy

Any gaps is filled with 0-
I know that I can create a loop to will solve me the problem, but is very slow.

Does anyone have any ideas how to optimize this?

Answer 1

I leave were the correct answer based on the help of everyone

-- dummy data
declare @table table
(
    DAY datetime,
    QTY int,
    Name nvarchar  (500) NULL
)
insert @table values('2010-1-1',  1, 'jack')
insert @table values('2010-1-3',  5,  'jack')
insert @table values('2010-1-2',  3 , 'wendy')
insert @table values('2010-1-6',  2 , 'wendy')


-- algorithm
DECLARE @output TABLE (
    DAY datetime,
    Qty int,
    Name varchar(25)
)
DECLARE @minMonth datetime, @maxMonth datetime, @lastName varchar(25)
SET @minMonth = '2010-1-1' 
SET @maxMonth = '2010-1-6';

WITH cte AS (
        SELECT @minMonth AS DateValue
    UNION ALL
        SELECT DATEADD(day, 1, DateValue)
        FROM cte
        WHERE DATEADD(day, 1, DateValue) <= @maxMonth
) 
INSERT INTO @output 
    SELECT 
        cte.DateValue, 
        ISNULL(tbl.qty,0), 
        tbl.Name
    FROM 
        cte cross JOIN 
        @table tbl

update @output
set qty = 0
where cast(DAY as nvarchar)+'@'+cast(Qty as nvarchar)+'@'+Name in 
(
    select cast(DAY as nvarchar)+'@'+cast(Qty as nvarchar)+'@'+Name from @output
    except
    select cast(DAY as nvarchar)+'@'+cast(Qty as nvarchar)+'@'+Name from @table
)

SELECT DAY, sum(qty) as qty, Name
FROM @output
GROUP BY DAY, Name
order by 3,1

and the output that I pretend

2010-01-01 00:00:00.000 1   jack
2010-01-02 00:00:00.000 0   jack
2010-01-03 00:00:00.000 5   jack
2010-01-04 00:00:00.000 0   jack
2010-01-05 00:00:00.000 0   jack
2010-01-06 00:00:00.000 0   jack
2010-01-01 00:00:00.000 0   wendy
2010-01-02 00:00:00.000 3   wendy
2010-01-03 00:00:00.000 0   wendy
2010-01-04 00:00:00.000 0   wendy
2010-01-05 00:00:00.000 0   wendy
2010-01-06 00:00:00.000 2   wendy

Although the solution is correct, doesn’t fit my need because recursion limitation.

Hopefully this script will help anyone with similar questions

Thank you to all