Consider the need to create a resultset of dates. We've got start and end dates, and we'd like to generate a list of dates in between.
DECLARE @Start datetime
,@End datetime
DECLARE @AllDates table
(@Date datetime)
SELECT @Start = 'Mar 1 2009', @End = 'Aug 1 2009'
--need to fill @AllDates. Trying to avoid looping.
-- Surely if a better solution exists.
Consider the current implementation with a WHILE
loop:
DECLARE @dCounter datetime
SELECT @dCounter = @Start
WHILE @dCounter <= @End
BEGIN
INSERT INTO @AllDates VALUES (@dCounter)
SELECT @dCounter=@dCounter+1
END
Question: How would you create a set of dates that are within a user-defined range using T-SQL? Assume SQL 2005+. If your answer is using SQL 2008 features, please mark as such.
If your dates are no more than 2047 days apart:
declare @dt datetime, @dtEnd datetime
set @dt = getdate()
set @dtEnd = dateadd(day, 100, @dt)
select dateadd(day, number, @dt)
from
(select number from master.dbo.spt_values
where [type] = 'P'
) n
where dateadd(day, number, @dt) < @dtEnd
I updated my answer after several requests to do so. Why?
The original answer contained the subquery
select distinct number from master.dbo.spt_values
where name is null
which delivers the same result, as I tested them on SQL Server 2008, 2012, and 2016.
However, as I tried to analyze the code that MSSQL internally when querying from spt_values
, I found that the SELECT
statements always contain the clause WHERE [type]='[magic code]'
.
Therefore I decided that although the query returns the correct result, it delivers the correct result for wrong reasons:
There may be a future version of SQL Server which defines a different [type]
value which also has NULL
as values for [name]
, outside the range of 0-2047, or even non-contiguous, in which case the result would be simply wrong.