T-SQL between periods gaps - sql

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

WITH DateRangeCTE([d]) AS
(
SELECT
CONVERT(DATETIME, '2010-01-01') AS [d]
UNION ALL
SELECT
DATEADD(d, 1, [d]) AS [d]
FROM
DateRangeCTE
WHERE [d] < DATEADD(d, -1, CONVERT(DATETIME, '2010-1-31'))
)
SELECT
DateRangeCTE.d, YourTable.Qty, YourTable.Name
FROM DateRangeCTE
LEFT JOIN YourTable ON DateRangeCTE.d = YourTable.DAY
If you get the error "The statement terminated. The maximum recursion 100 has been exhausted before statement completion." then use the maxrecursion hint.

Answer 2

Here's a solution that you can use if you don't know the date range in advance. It derives the date range based on the data. The solution uses a numbers table, which uses an existing table in the master database (spt_values).
WITH MinMax AS
( SELECT DISTINCT [Name],
MIN([DAY]) OVER () AS min_day, MAX([DAY]) OVER () AS max_day
FROM mytable
)
, DateRange AS
( SELECT MinMax.[Name], DATEADD(mm, n.number, MinMax.min_day) AS [Date]
FROM MinMax
JOIN master.dbo.spt_values n ON n.type = 'P'
AND DATEADD(mm, n.number, MinMax.min_day) <= MinMax.max_day
)
SELECT dr.[Name], COALESCE(mt.[qty], 0) AS [QTY], dr.Date
FROM DateRange dr
LEFT OUTER JOIN MyTable mt ON dr.Name = mt.Name AND mt.Day = dr.Date
ORDER BY dr.Name, dr.Date ;

Answer 3

Here's another way:
DECLARE #output TABLE (
DateValue datetime,
Qty varchar(50),
LastName varchar(25)
PRIMARY KEY (DateValue, LastName)
)
DECLARE #minMonth datetime, #maxMonth datetime, #lastName varchar(25)
-- whatever your business logic dictates for these
SET #minMonth = '01/01/2010'
SET #maxMonth = '12/01/2010';
with cte as (
SELECT #minMonth AS DateValue
UNION ALL
SELECT DATEADD(month, 1, DateValue)
FROM cte
WHERE DATEADD(month, 1, DateValue) <= #maxMonth
)
INSERT INTO #output (DateValue, Qty, LastName)
SELECT cte.DateValue,
ISNULL(tbl.Alias,0),
tbl.Name
FROM cte LEFT JOIN dbo.YourTable tbl ON tbl.[Day] = cte.Mth
UPDATE #output SET
LastName = CASE WHEN LastName IS NULL THEN #lastName ELSE LastName END,
#lastName = LastName
FROM #output
SELECT * FROM #output

Answer 4

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