Get a list of dates between two dates using a function

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 exa

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

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'

Answer 3

This does exactly what you want, modified from Will's earlier post. No need for helper tables or loops.

WITH date_range (calc_date) AS (
    SELECT DATEADD(DAY, DATEDIFF(DAY, 0, '2010-01-13') - DATEDIFF(DAY, '2010-01-01', '2010-01-13'), 0)
        UNION ALL SELECT DATEADD(DAY, 1, calc_date)
            FROM date_range
            WHERE DATEADD(DAY, 1, calc_date) <= '2010-01-13')
SELECT calc_date
FROM date_range;

Answer 4

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 5

this few lines are the simple answer for this question in sql server.

WITH mycte AS
(
  SELECT CAST('2011-01-01' AS DATETIME) DateValue
  UNION ALL
  SELECT  DateValue + 1
  FROM    mycte   
  WHERE   DateValue + 1 < '2021-12-31'
)

SELECT  DateValue
FROM    mycte
OPTION (MAXRECURSION 0)

Answer 6

DECLARE @StartDate DATE = '2017-09-13',         @EndDate DATE = '2017-09-16'

SELECT date  FROM (   SELECT DATE = DATEADD(DAY, rn - 1, @StartDate)   FROM    (
    SELECT TOP (DATEDIFF(DAY, @StartDate, DATEADD(DAY,1,@EndDate)))
      rn = ROW_NUMBER() OVER (ORDER BY s1.[object_id])
    FROM sys.all_objects AS s1
    CROSS JOIN sys.all_objects AS s2
    ORDER BY s1.[object_id]   ) AS x ) AS y

Result:

2017-09-13

2017-09-14

2017-09-15

2017-09-16