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TSQL - checking for the intersection of two sets of dates

Double post day!

The same query that had concatenation happening from the previous post also had date range parameters, @StartDate and @EndDate, and needed to only return records (which also had their own start/end date fields) in which the records' were active during the specified date range.  I.e. where the record's date range intersected with the date range parameters.  It confused me for a bit so I'm recording for posterity. As I see it, there are three possible valid cases:

Case 1: Record's start date is within the date range



Case 2: Record's end is within the date range


Case 3: Record's end IS NULL (i.e. still currently active) and record's start is less than the end of the date range



So expressed in code, these three cases looked like this:

SELECT SomeFields
FROM  SomeTable t

--case 1
WHERE ((t.Start >= @StartDate
AND   t.Start < @EndDate)

--case 2
OR    (t.End > @StartDate
AND   t.End <= @EndDate)

--case 3
OR    (t.End IS NULL
AND   t.Start < @EndDate))


If you notice any issues or potential for improvement, please let me know! :)

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