You can use isnull to take care of the parameters when they are null.
Something like this should do what you want.
select T.*
from #TempTbl as T
where T.StartDtm <= isnull(@StopDtm, '99991231') and
(T.StopDtm >= isnull(@StartDtm, '17530101') or T.StopDtm is null)
The only truly safe formats for DATETIME/SMALLDATETIME in SQL Server are:
yyyyMMdd
yyyyMMdd hh:nn:ss[.mmmmmmm]
yyyy-MM-ddThh:nn:ss[.mmmmmmm]
----------^ yes, that T is important!
Anything else is subject to incorrect interpretation by SQL Server, Windows, the provider, the application code, end users, etc. For example, the following always breaks:*
SET LANGUAGE FRENCH;
SELECT CONVERT(DATETIME, '2013-11-13');
Result:
Le paramètre de langue est passé à Français.
Msg 242, Level 16, State 3, Line 2
La conversion d'un type de données varchar en type de données datetime a créé une valeur hors limites.
Just changing the language (which any of your user sessions can do) forced SQL Server to interpret that as YYYY-DD-MM instead of YYYY-MM-DD. Similar things can happen with setting like DATEFORMAT. But these settings are literally ignored when using the above two formats.
Always, always, always use one of the above two formats. If you are passing a variable as a string, stop doing that. If you can't, check to make sure it passes ISDATE() first. If you are letting people type any date string into a form field, stop doing that, too. Use a date-picker or calendar control and dictate the format of the string before you pass it to SQL Server. Well, depending on the language, just keep it as a datetime value and don't convert it to a string at all.
Please read this post:
There is an exception: SELECT CONVERT(DATE, 'yyyy-mm-dd'); will not break. But I err on the side of consistency rather than using a format only in the one place where I know it doesn't break, and having to use a safer format everywhere else.
Best Answer
This looks like a case where the date column isn't a date at all, but rather a string.
You aren't getting Nov 2 through Nov 9 because the sorting on the string and calculating if it's less than
11/1....in alphanumeric order.Ideally, dates will be stored as dates, and then your existing query will work. This will also ensure that dates are valid dates, and you don't end up with data for 32 February, or even random strings.
If you can't change the type of the column, you'll have to cast the database values to a date to do the comparison (which will hurt performance, but get you the results you expect).