[sql-server] Get a list of dates between two dates using a function

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.

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.

In case you want to print years starting from a particular year till current date. Just altered the accepted answer.

WITH mycte AS
    (
      SELECT YEAR(CONVERT(DATE, '2006-01-01',102)) DateValue
      UNION ALL
      SELECT  DateValue + 1
      FROM    mycte   
      WHERE   DateValue + 1 < = YEAR(GETDATE())
    )
    SELECT  DateValue
    FROM    mycte

OPTION (MAXRECURSION 0)

DECLARE @MinDate DATETIME = '2012-09-23 00:02:00.000',
    @MaxDate DATETIME = '2012-09-25 00:00:00.000';

SELECT  TOP (DATEDIFF(DAY, @MinDate, @MaxDate) + 1) Dates = DATEADD(DAY, ROW_NUMBER() OVER(ORDER BY a.object_id) - 1, @MinDate)
FROM sys.all_objects a CROSS JOIN sys.all_objects b;

-- ### 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;

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

Before you use my function, you need to set up a "helper" table, you only need to do this one time per database:

CREATE TABLE Numbers
(Number int  NOT NULL,
    CONSTRAINT PK_Numbers PRIMARY KEY CLUSTERED (Number ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
DECLARE @x int
SET @x=0
WHILE @x<8000
BEGIN
    SET @x=@x+1
    INSERT INTO Numbers VALUES (@x)
END

here is the function:

CREATE FUNCTION dbo.ListDates
(
     @StartDate    char(10)  
    ,@EndDate      char(10)
)
RETURNS
@DateList table
(
    Date datetime
)
AS
BEGIN


IF ISDATE(@StartDate)!=1 OR ISDATE(@EndDate)!=1
BEGIN
    RETURN
END

INSERT INTO @DateList
        (Date)
    SELECT
        CONVERT(datetime,@StartDate)+n.Number-1
        FROM Numbers  n
        WHERE Number<=DATEDIFF(day,@StartDate,CONVERT(datetime,@EndDate)+1)


RETURN

END --Function

use this:

select * from dbo.ListDates('2010-01-01', '2010-01-13')

output:

Date
-----------------------
2010-01-01 00:00:00.000
2010-01-02 00:00:00.000
2010-01-03 00:00:00.000
2010-01-04 00:00:00.000
2010-01-05 00:00:00.000
2010-01-06 00:00:00.000
2010-01-07 00:00:00.000
2010-01-08 00:00:00.000
2010-01-09 00:00:00.000
2010-01-10 00:00:00.000
2010-01-11 00:00:00.000
2010-01-12 00:00:00.000
2010-01-13 00:00:00.000

(13 row(s) affected)

Answer is avialbe here How to list all dates between two dates

Create Procedure SelectDates(@fromDate Date, @toDate Date)
AS
BEGIN
    SELECT DATEADD(DAY,number,@fromDate) [Date]
    FROM master..spt_values
    WHERE type = 'P'
    AND DATEADD(DAY,number,@fromDate) < @toDate

END

All you have to do is just change the hard coded value in the code provided below

DECLARE @firstDate datetime
    DECLARE @secondDate datetime
    DECLARE @totalDays  INT
    SELECT @firstDate = getDate() - 30
    SELECT @secondDate = getDate()

    DECLARE @index INT
    SELECT @index = 0
    SELECT @totalDays = datediff(day, @firstDate, @secondDate)

    CREATE TABLE #temp
    (
         ID INT NOT NULL IDENTITY(1,1)
        ,CommonDate DATETIME NULL
    )

    WHILE @index < @totalDays
        BEGIN

            INSERT INTO #temp (CommonDate) VALUES  (DATEADD(Day, @index, @firstDate))   
            SELECT @index = @index + 1
        END

    SELECT CONVERT(VARCHAR(10), CommonDate, 102) as [Date Between] FROM #temp

    DROP TABLE #temp

Perhaps if you wish to go an easier way, this should do it.

WITH date_range (calc_date) AS (
    SELECT DATEADD(DAY, DATEDIFF(DAY, 0, CURRENT_TIMESTAMP) - 6, 0)
        UNION ALL SELECT DATEADD(DAY, 1, calc_date)
            FROM date_range
            WHERE DATEADD(DAY, 1, calc_date) < CURRENT_TIMESTAMP)
SELECT calc_date
FROM date_range;

But the temporary table is a very good approach also. Perhaps shall you also consider a populated calendar table.

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;

A few ideas:

If you need the list dates in order to loop through them, you could have a Start Date and Day Count parameters and do a while loop whilst creating the date and using it?

Use C# CLR Stored Procedures and write the code in C#

Do this outside the database in code

This query works on Microsoft SQL Server.

select distinct format( cast('2010-01-01' as datetime) + ( a.v / 10 ), 'yyyy-MM-dd' ) as aDate
       from (
             SELECT ones.n + 10 * tens.n + 100 * hundreds.n + 1000 * thousands.n as v
             FROM (VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) ones(n),
                    (VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) tens(n),
                    (VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) hundreds(n),
                  (VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) thousands(n)
       ) a
       where format( cast('2010-01-01' as datetime) + ( a.v / 10 ), 'yyyy-MM-dd' ) < cast('2010-01-13' as datetime)
       order by aDate asc;

Now let's look at how it works.

The inner query merely returns a list of integers from 0 to 9999. It will give us a range of 10,000 values for calculating dates. You can get more dates by adding rows for ten_thousands and hundred_thousands and so forth.

SELECT ones.n + 10 * tens.n + 100 * hundreds.n + 1000 * thousands.n as v
         FROM (VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) ones(n),
                (VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) tens(n),
                (VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) hundreds(n),
              (VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) thousands(n)
   ) a;

This part converts the string to a date and adds a number to it from the inner query.

cast('2010-01-01' as datetime) + ( a.v / 10 )

Then we convert the result into the format you want. This is also the column name!

format( cast('2010-01-01' as datetime) + ( a.v / 10 ), 'yyyy-MM-dd' )

Next we extract only the distinct values and give the column name an alias of aDate.

distinct format( cast('2010-01-01' as datetime) + ( a.v / 10 ), 'yyyy-MM-dd' ) as aDate

We use the where clause to filter in only dates within the range you want. Notice that we use the column name here since SQL Server does not accept the column alias, aDate, within the where clause.

where format( cast('2010-01-01' as datetime) + ( a.v / 10 ), 'yyyy-MM-dd' ) < cast('2010-01-13' as datetime)

Lastly, we sort the results.

   order by aDate asc;

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

I'm an oracle guy, but I believe MS SQL Server has support for the connect by clause:

select  sysdate + level
from    dual
connect by level <= 10 ;

The output is:

SYSDATE+LEVEL
05-SEP-09
06-SEP-09
07-SEP-09
08-SEP-09
09-SEP-09
10-SEP-09
11-SEP-09
12-SEP-09
13-SEP-09
14-SEP-09

Dual is just a 'dummy' table that comes with oracle (it contains 1 row and the word 'dummy' as the value of the single column).

WITH TEMP (DIA, SIGUIENTE_DIA ) AS
           (SELECT 
               1, 
               CAST(@FECHAINI AS DATE)
            FROM 
               DUAL
           UNION ALL
            SELECT 
               DIA, 
               DATEADD(DAY, DIA, SIGUIENTE_DIA)
            FROM 
               TEMP
            WHERE
               DIA < DATEDIFF(DAY,  @FECHAINI, @FECHAFIN)   
               AND DATEADD(DAY, 1, SIGUIENTE_DIA) <=  CAST(@FECHAFIN AS DATE)
           )
           SELECT 
              SIGUIENTE_DIA AS CALENDARIO 
           FROM
              TEMP
           ORDER BY   
              SIGUIENTE_DIA

The detail is on the table DUAL but if your exchange this table for a dummy table this works.

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 adddate('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'

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
            )

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

Declare @date1 date = '2016-01-01'
              ,@date2 date = '2016-03-31'
              ,@date_index date
Declare @calender table (D date)
SET @date_index = @date1
WHILE @date_index<=@date2
BEGIN
INSERT INTO @calender
SELECT @date_index

SET @date_index = dateadd(day,1,@date_index)

IF @date_index>@date2
Break
ELSE
Continue
END

Definately a numbers table, though tyou may want to use Mark Redman's idea of a CLR proc/assembly if you really need the performance.

How to create the table of dates (and a super fast way to create a numbers table)

/*Gets a list of integers into a temp table (Jeff Moden's idea from SqlServerCentral.com)*/
 SELECT TOP 10950 /*30 years of days*/
        IDENTITY(INT,1,1) as N
   INTO #Numbers
   FROM Master.dbo.SysColumns sc1,
        Master.dbo.SysColumns sc2


/*Create the dates table*/
CREATE TABLE [TableOfDates](
    [fld_date] [datetime] NOT NULL,
 CONSTRAINT [PK_TableOfDates] PRIMARY KEY CLUSTERED 
(
    [fld_date] ASC
)WITH FILLFACTOR = 99 ON [PRIMARY]
) ON [PRIMARY]

/*fill the table with dates*/
DECLARE @daysFromFirstDateInTheTable int
DECLARE @firstDateInTheTable DATETIME

SET @firstDateInTheTable = '01/01/1998'
SET @daysFromFirstDateInTheTable = (SELECT (DATEDIFF(dd, @firstDateInTheTable ,GETDATE()) + 1))

INSERT INTO
      TableOfDates
SELECT 
      DATEADD(dd,nums.n - @daysFromFirstDateInTheTable, CAST(FLOOR(CAST(GETDATE() as FLOAT)) as DateTime)) as FLD_Date
FROM #Numbers nums

Now that you have a table of dates, you can use a function (NOT A PROC) like KM's to get the table of them.

CREATE FUNCTION dbo.ListDates
(
     @StartDate    DATETIME  
    ,@EndDate      DATETIME
)
RETURNS
@DateList table
(
    Date datetime
)
AS
BEGIN

/*add some validation logic of your own to make sure that the inputs are sound.Adjust the rest as needed*/

  INSERT INTO
    @DateList
  SELECT FLD_Date FROM TableOfDates (NOLOCK) WHERE FLD_Date >= @StartDate AND FLD_Date <= @EndDate
  RETURN
END