SQL Server stored procedure optional parameters, include all if null - sql

Question

I have this stored procedure:
ALTER PROCEDURE [dbo].[GetCalendarEvents]
(#StartDate datetime,
#EndDate datetime,
#Location varchar(250) = null)
AS
BEGIN
SELECT *
FROM Events
WHERE EventDate >= #StartDate
AND EventDate <= #EndDate
AND (Location IS NULL OR Location = #Location)
END
Now, I have the location parameter, what I want to do is if the parameter is not null then include the parameter in where clause. If the parameter is null I want to completely ignore that where parameter and only get the result by start and end date.
Because when I'm doing this for example:
EXEC GetCalendarEvents '02/02/2014', '10/10/2015', null
I'm not getting any results because there are other locations which are not null and since the location parameter is null, I want to get the results from all the locations.
Any idea how can I fix this?

Answer 1

ALTER PROCEDURE [dbo].[GetCalendarEvents]
( #StartDate DATETIME,
#EndDate DATETIME,
#Location VARCHAR(250) = NULL
)
AS
BEGIN
SELECT *
FROM events
WHERE EventDate >= #StartDate
AND EventDate <= #EndDate
AND Location = ISNULL(#Location, Location )
END
If a NULL column is a possibility, then this would work.
ALTER PROCEDURE [dbo].[GetCalendarEvents]
( #StartDate DATETIME,
#EndDate DATETIME,
#Location VARCHAR(250) = NULL
)
AS
BEGIN
IF ( #loc IS NULL )
BEGIN
SELECT *
FROM events
WHERE EventDate >= #StartDate
AND EventDate <= #EndDate
END
ELSE
BEGIN
SELECT *
FROM events
WHERE EventDate >= #StartDate
AND EventDate <= #EndDate
AND Location = #Location
END
END
As having an 'OR' clause should be reasonably avoided due to possible performance issues.

Answer 2

The part in the WHERE clause should then read
AND (#Location IS NULL OR Location=#Location)

Answer 3

Try this
SELECT *
FROM Events
WHERE EventDate >= #StartDate
AND EventDate <= #EndDate
AND Location = Case When LEN(#Location) > 0 Then #Location Else Location End

Answer 4

It can be easily done with a dynamic sql query.
ALTER PROCEDURE [dbo].[GetCalendarEvents]
(#StartDate datetime,
#EndDate datetime,
#Location varchar(250) = null)
AS
BEGIN
DECLARE #SQL NVARCHAR(MAX);
DECLARE #PARAMETER_DEFIINITION NVARCHAR(MAX);
DECLARE #WHERE_PART NVARCHAR(MAX);
SET #PARAMETER_DEFIINITION =' #StartDate DATETIME, #EndDate DATETIME, #Location VARCHAR(250) '
SET #SQL ='SELECT *
FROM Events
WHERE EventDate >= #StartDate
AND EventDate <= #EndDate '
IF #Location IS NOT NULL
BEGIN
SET #WHERE_PART = ' AND Location = #Location '
END
SET #SQL = #SQL + #WHERE_PART
EXEC SP_EXECUTESQL #SQL, #PARAMETER_DEFIINITION, #StartDate, #EndDate, #Location
END
Query will be dynamically created according to the parameters. In here if #location is null then it will not add to the where part.
If you want more on writing dynamic queries please refer this article. http://codingpulse.blogspot.com/2015/02/dynamic-sql-in-stored-procedure-part-1.html