This is how to run a SQL Query where you have two date columns and like to see if your date falls between those columns;
SELECT * FROM FiscalCalendarRef
WHERE 1=1
AND '2021-09-13' BETWEEN StartDate AND EndDate
If EndDate column is defined as NULL, you can change it like this;
SELECT * FROM FiscalCalendarRef
WHERE 1=1
AND '2021-09-13' BETWEEN StartDate AND COALESCE(EndDate, GETDATE())
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