My question is similar to this one with (I think) significant enough difference. I have a base range and I want to find all other ranges in a table that conflict with it and each other. or rather the items that form the ranges, but it doesn't really make a difference.
The line with a asterisk is the starting range. The ranges 1,2 and 3 are the ones that are supposed to expand it. The result range should be the X.
1 | 3 | ===1==== ==== 5 | ==2== ====*==== ==== 6 | ====3==== ===== --+------------------------------------- | |<--------X-------->|
I have written this:
WITH cte AS ( SELECT DATA1.ID, DATA1.STARTDATE, DATA1.ENDDATE FROM DATA1 WHERE DATA1.ID = @PARID AND DATA1.STARTDATE > @STARTDATE AND DATA1.ENDDATE < @ENDDATE UNION ALL SELECT DATA1.ID, DATA1.STARTDATE, DATA1.ENDDATE FROM cte INNER JOIN DATA1 ON (DATA1.ID = cte.ID) WHERE DATA1.ID = @PARID AND (cte.STARTDATE < DATA1.ENDDATE AND cte.ENDDATE > DATA1.ENDDATE) ) SELECT * FROM cte
But after some fiddling realized this can't really work, since the 2nd SELECT doesn't know what
ENDDATE it should use from the
cte. And I can't use subqueries in recursive SQL.
We have previously calculated this in client in .NET via set of recursive functions, but at O(N^2) it was stupidly slow. The intent here is to move the calculations to the server as well as optimize the calculation.
Is what I'm trying to do here at all viable?
SQL Fiddle. I'm having some trouble getting the query to run as it did on my machine (where I used less simple data structure), but at least I added example data. I will keep trying to get it to produce the same result I got on my machine.
With input range from
2018-08-24 12:00:00 to
2018-08-31 12:00:00, the correct output should be IDs
2, 3, 4, 6.