OPTION(MAXRECURSION 0) in SQL Server - sql

Question

I am used this function to execute stored procedure,
FUNCTION [dbo].[Test]
(#d1 DATE,
#d2 DATE,
#nd VARCHAR(MAX))
RETURNS TABLE
AS
RETURN
(WITH AllDates AS
(
SELECT #d1 AS DateOf
UNION ALL
SELECT DATEADD (DAY, 1, DateOf­)
FROM AllDates
WHERE DateOf < #d2
)
SELECT COUNT() SumOfDays
FROM AllDates
WHERE EXISTS (SELECT 1
FROM STRING_SPLIT(#nd,' ')
WHERE DATENAME(weekday,dat­eof) = value)
OPTION (MAXRECURSION 0)
)
The result is supposed to know how many of 'Monday Tuesday Saturday' are between Date1 And Date 2
n.b i need to add OPTION(MAXRECURSION 0) in the function but it's not working ,
But I get this error:
Incorrect syntax near the keyword 'OPTION'.

Answer 1

OPTION clause can be used only at the statement level. So you cannot use it within a query expression inside view definitions or inline TVFs etc. The only way to use it in your case is to create the TVF without the OPTION clause and specify it in the query that uses the TVF. We have a bug that tracks request for allowing use of OPTION clause inside any query expression (for example, if exists() or CTE or view).
Here is the that that you can visit to refer more: https://social.msdn.microsoft.com/Forums/sqlserver/en-US/7c7d5fea-38ad-4bc5-9038-a157e640561f/using-option-clause-within-create-function-statement-for-inline-table-functions?forum=transactsql
So in your example, you must specify the OPTION when you call your function:
FUNCTION [dbo].[Test](#d1 DATE, #d2 DATE, #nd VARCHAR(MAX))
RETURNS TABLE
AS
RETURN (
WITH AllDates AS
(
SELECT #d1 AS DateOf
UNION ALL
SELECT DateAdd(day,1,DateOf­)
FROM AllDates
WHERE DateOf<#d2
)
select COUNT() SumOfDays
FROM AllDates
WHERE EXISTS(SELECT 1
FROM STRING_SPLIT(#nd,' ')
WHERE DATENAME(weekday,dat­eof) = value)
)
Now you can use Option at SELECT statement:
SELECT * FROM [dbo].[Test] ( #d1 , #d2, #nd ) OPTION ( MAXRECURSION 0 )
Hope to help, my friend :))

Answer 2

The obvious answer to stop the recursion error would be to get rid of the recursion. If there's no recursion then there's no problem!
This is very simple to do as well, as you simply use a tally instead. This also has a speed benefit, as a Tally is (significantly) faster than a rCTE. I use an inline tally for this:
CREATE FUNCTION dbo.Test (#D1 date, #D2 date, #nd varchar(100)) --There's no need for MAX
RETURNS TABLE
AS
RETURN (WITH N AS(
SELECT N
FROM (VALUES(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL))N(N)),
Tally AS(
SELECT TOP (SELECT DATEDIFF(DAY,#D1,#D2)) --It appears you don't include the last day in your logic
--If it should, add +1 to the DATEDIFF value
ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) -1 AS I
FROM N N1, N N2, N N3, N N4, N N5), --More than enough rows
Dates AS(
SELECT DATEADD(DAY, T.I, #D1) AS D
FROM Tally T)
SELECT COUNT(D.D) AS SumOfDays
FROM Dates D
WHERE EXISTS(SELECT 1
FROM STRING_SPLIT(#nd,' ')
WHERE DATENAME(weekday,D.D) = value))
GO
SELECT *
FROM dbo.Test('20000101','20200101','Sunday Saturday');
GO
DROP FUNCTION dbo.Test;
I change the length of #nd as there's no need for it to be a MAX. The string 'Sunday Monday Tuesday Wednesday Thursday Friday Saturday' is only 56 characters long, so a varchar(100) is more than enough. You may, however, want to use an nvarchar, to ensure this function works for other languages; as a character may end up being lost.

Answer 3

The option is associated with the outermost select:
RETURN (
WITH AllDates AS(
SELECT #d1 AS DateOf
UNION ALL
SELECT DATEADD (DAY, 1, DateOf­)
FROM AllDates
WHERE DateOf < #d2
)
SELECT COUNT() SumOfDays
FROM AllDates
WHERE EXISTS (SELECT 1
FROM STRING_SPLIT(#nd,' ')
WHERE DATENAME(weekday,dat­eof) = value)
)
OPTION (MAXRECURSION 0)
)