Get a list of dates between two dates using a func

Question

My question is similar to this MySQL question, but intended for SQL Server:

Is there a function or a query that will return a list of days between two dates? For example, lets say there is a function called ExplodeDates:

SELECT ExplodeDates('2010-01-01', '2010-01-13');

This would return a single column table with the values:

2010-01-01
2010-01-02
2010-01-03
2010-01-04
2010-01-05
2010-01-06
2010-01-07
2010-01-08
2010-01-09
2010-01-10
2010-01-11
2010-01-12
2010-01-13

I'm thinking that a calendar/numbers table might be able to help me here.

---

Update

I decided to have a look at the three code answers provided, and the results of the execution - as a % of the total batch - are:

• Rob Farley's answer : 18%
• StingyJack's answer : 41%
• KM's answer : 41%

Lower is better

I have accepted Rob Farley's answer, as it was the fastest, even though numbers table solutions (used by both KM and StingyJack in their answers) are something of a favourite of mine. Rob Farley's was two-thirds faster.

Update 2

Alivia's answer is much more succinct. I have changed the accepted answer.

Answer 1

Try something like this:

CREATE FUNCTION dbo.ExplodeDates(@startdate datetime, @enddate datetime)
returns table as
return (
with 
 N0 as (SELECT 1 as n UNION ALL SELECT 1)
,N1 as (SELECT 1 as n FROM N0 t1, N0 t2)
,N2 as (SELECT 1 as n FROM N1 t1, N1 t2)
,N3 as (SELECT 1 as n FROM N2 t1, N2 t2)
,N4 as (SELECT 1 as n FROM N3 t1, N3 t2)
,N5 as (SELECT 1 as n FROM N4 t1, N4 t2)
,N6 as (SELECT 1 as n FROM N5 t1, N5 t2)
,nums as (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 1)) as num FROM N6)
SELECT DATEADD(day,num-1,@startdate) as thedate
FROM nums
WHERE num <= DATEDIFF(day,@startdate,@enddate) + 1
);

You then use:

SELECT *
FROM dbo.ExplodeDates('20090401','20090531') as d;

Edited (after the acceptance):

Please note... if you already have a sufficiently large nums table then you should use:

CREATE FUNCTION dbo.ExplodeDates(@startdate datetime, @enddate datetime)
returns table as
return (
SELECT DATEADD(day,num-1,@startdate) as thedate
FROM nums
WHERE num <= DATEDIFF(day,@startdate,@enddate) + 1
);

And you can create such a table using:

CREATE TABLE dbo.nums (num int PRIMARY KEY);
INSERT dbo.nums values (1);
GO
INSERT dbo.nums SELECT num + (SELECT COUNT(*) FROM nums) FROM nums
GO 20

These lines will create a table of numbers containing 1M rows... and far quicker than inserting them one by one.

You should NOT create your ExplodeDates function using a function that involves BEGIN and END, as the Query Optimizer becomes unable to simplify the query at all.

Answer 2

Would all these dates be in the database already or do you just want to know the days between the two dates? If it's the first you could use the BETWEEN or <= >= to find the dates between

EXAMPLE:

SELECT column_name(s)
FROM table_name
WHERE column_name
BETWEEN value1 AND value2

OR

SELECT column_name(s)
FROM table_name
WHERE column_name
value1 >= column_name
AND column_name =< value2

Answer 3

-- ### Six of one half dozen of another. Another method assuming MsSql

Declare @MonthStart    datetime   = convert(DateTime,'07/01/2016')
Declare @MonthEnd      datetime   = convert(DateTime,'07/31/2016')
Declare @DayCount_int       Int   = 0 
Declare @WhileCount_int     Int   = 0

set @DayCount_int = DATEDIFF(DAY, @MonthStart, @MonthEnd)
select @WhileCount_int
WHILE @WhileCount_int < @DayCount_int + 1
BEGIN
   print convert(Varchar(24),DateAdd(day,@WhileCount_int,@MonthStart),101)
   SET @WhileCount_int = @WhileCount_int + 1;
END;

Answer 4

SELECT  dateadd(dd,DAYS,'2013-09-07 00:00:00') DATES
INTO        #TEMP1
FROM
(SELECT TOP 365 colorder - 1 AS DAYS from master..syscolumns 
    WHERE id = -519536829 order by colorder) a

WHERE datediff(dd,dateadd(dd,DAYS,'2013-09-07 00:00:00'),'2013-09-13 00:00:00' ) >= 0 
    AND  dateadd(dd,DAYS,'2013-09-07 00:00:00') <=  '2013-09-13 00:00:00'  
    SELECT * FROM #TEMP1

Answer 5

A Bit late to the party, but I like this solution quite a bit.

CREATE FUNCTION ExplodeDates(@startDate DateTime, @endDate DateTime)
RETURNS table as
return (
    SELECT  TOP (DATEDIFF(DAY, @startDate, @endDate) + 1)
            DATEADD(DAY, ROW_NUMBER() OVER(ORDER BY a.object_id) - 1, @startDate) AS DATE
    FROM    sys.all_objects a
            CROSS JOIN sys.all_objects b
            )

Answer 6

if you're in a situation like me where procedures and functions are prohibited, and your sql user does not have permissions for insert, therefore insert not allowed, also "set/declare temporary variables like @c is not allowed", but you want to generate a list of dates in a specific period, say current year to do some aggregation, use this

select * from 
(select affffdate('1970-01-01',t4*10000 + t3*1000 + t2*100 + t1*10 + t0) gen_date from
 (select 0 t0 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t0,
 (select 0 t1 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t1,
 (select 0 t2 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t2,
 (select 0 t3 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t3,
 (select 0 t4 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t4) v
where gen_date between '2017-01-01' and '2017-12-31'