This SQL Server User Defined Function resolves the problem efficiently.No recursion, no complex loops. It takes a very short time to generate.
ALTER FUNCTION [GA].[udf_GenerateCalendar]
(
@StartDate DATE -- StartDate
, @EndDate DATE -- EndDate
)
RETURNS @Results TABLE
(
Date DATE
)
AS
/**********************************************************
Purpose: Generate a sequence of dates based on StartDate and EndDate
***********************************************************/
BEGIN
DECLARE @counter INTEGER = 1
DECLARE @days table(
day INTEGER NOT NULL
)
DECLARE @months table(
month INTEGER NOT NULL
)
DECLARE @years table(
year INTEGER NOT NULL
)
DECLARE @calendar table(
Date DATE NOT NULL
)
-- Populate generic days
SET @counter = 1
WHILE @counter <= 31
BEGIN
INSERT INTO @days
SELECT @counter dia
SELECT @counter = @counter + 1
END
-- Populate generic months
SET @counter = 1
WHILE @counter <= 12
BEGIN
INSERT INTO @months
SELECT @counter month
SELECT @counter = @counter + 1
END
-- Populate generic years
SET @counter = YEAR(@StartDate)
WHILE @counter <= YEAR(@EndDate)
BEGIN
INSERT INTO @years
SELECT @counter year
SELECT @counter = @counter + 1
END
INSERT @calendar (Date)
SELECT Date
FROM (
SELECT
CONVERT(Date, [Date], 102) AS Date
FROM (
SELECT
CAST(
y.year * 10000
+ m.month * 100
+ d.day
AS VARCHAR(8)) AS Date
FROM @days d, @months m, @years y
WHERE
ISDATE(CAST(
y.year * 10000
+ m.month * 100
+ d.day
AS VARCHAR(8))
) = 1
) A
) A
INSERT @Results (Date)
SELECT Date
FROM @calendar
WHERE Date BETWEEN @StartDate AND @EndDate
RETURN
/*
DECLARE @StartDate DATE = '2015-08-01'
DECLARE @EndDate DATE = '2015-08-31'
select * from [GA].[udf_GenerateCalendar](@StartDate, @EndDate)
*/
END
