Can I use recursion in a Sql Server 2005 View?
-
05-07-2019 - |
Question
I tried to use OPTION (MAXRECURSION 0)
in a view to generate a list of dates.
This seems to be unsupported. Is there a workaround for this issue?
EDIT to Explain what I actually want to do:
I have 2 tables.
table1: int weekday, bool available
table2: datetime date, bool available
I want the result: view1: date (here all days in this year), available(from table2 or from table1 when not in table2).
That means I have to apply a join on a date with a weekday. I hope this explanation is understandable, because I actually use more tables with more fields in the query.
I found this code to generate the recursion:
WITH Dates AS
(
SELECT cast('2008-01-01' as datetime) Date
UNION ALL
SELECT Date + 1
FROM Dates
WHERE Date + 1 < DATEADD(yy, 1, GETDATE())
)
Solution
No - if you can find a way to do it within 100 levels of recusion (have a table of numbers), which will get you to within 100 recursion levels, you'll be able to do it. But if you have a numbers or pivot table, you won't need the recursion anyway...
See this question (but I would create a table and not a table-valued function), this question and this link and this link
OTHER TIPS
You can use a CTE for hierarchical queries.
Here you go:
;WITH CTE_Stack(IsPartOfRecursion, Depth, MyDate) AS
(
SELECT
0 AS IsPartOfRecursion
,0 AS Dept
,DATEADD(DAY, -1, CAST('01.01.2012' as datetime)) AS MyDate
UNION ALL
SELECT
1 AS IsPartOfRecursion
,Parent.Depth + 1 AS Depth
--,DATEADD(DAY, 1, Parent.MyDate) AS MyDate
,DATEADD(DAY, 1, Parent.MyDate) AS MyDate
FROM
(
SELECT 0 AS Nothing
) AS TranquillizeSyntaxCheckBecauseWeDontHaveAtable
INNER JOIN CTE_Stack AS Parent
--ON Parent.Depth < 2005
ON DATEADD(DAY, 1, Parent.MyDate) < DATEADD(YEAR, 1, CAST('01.01.2012' as datetime))
)
SELECT * FROM CTE_Stack
WHERE IsPartOfRecursion = 1
OPTION (MAXRECURSION 367) -- Accounting for leap-years
;