Using WHERE clause with BETWEEN and null date parameters

Question

One of my WHERE clauses is the following:

AND (DateCreated BETWEEN @DateFrom and @DateTo OR (@DateFrom IS NULL OR @DateTo IS NULL))

@DateFrom and @DateTo are input parameters that may be NULL.

If they are both null, then I need to basically ignore the BETWEEN and return all records.

If @DateFrom is NULL, but @DateTo is NOT NULL, then I need to return all records with DateCreated being no greater than @DateTo (inclusive).

If @DateFrom is NOT NULL, but @DateTo is NULL, then I need to return all records with DateCreated being no earlier than @DateFrom (inclusive) up to today's date.

DateCreated is not a null or some time it is null field.

So far my WHERE clause is not working exactly like I want.

Answer 1

Just need some extra criteria to handle when one or the other is NULL:

AND (
    (DateCreated >= @DateFrom and DateCreated < DATEADD(day,1,@DateTo)) 
 OR (@DateFrom IS NULL AND @DateTo IS NULL)
 OR (@DateFrom IS NULL AND DateCreated < DATEADD(day,1,@DateTo))
 OR (@DateTo IS NULL AND DateCreated >= @DateFrom)
    )

Edit: Giorgi's approach was simpler, here it is adapted for use with DATETIME:

AND (       (DateCreated >= @DateFrom OR @DateFrom IS NULL) 
        AND (DateCreated < DATEADD(day,1,@DateTo) OR @DateTo IS NULL)
    )

The issue with BETWEEN or <= when using a DATE variable against a DATETIME field, is that any time after midnight on the last day will be excluded.

'2015-02-11 13:07:56.017' is greater than '2015-02-11' Rather than casting your field as DATE for comparison, it's better for performance to add a day to your variable and change from <= to <.

Answer 2

Try this:

WHERE ((DateCreated >= @DateFrom OR @DateFrom IS NULL) AND (DateCreated =< @DateTo OR @DateTo IS NULL))