Question

I have a query in sql server 2008. That I want to either pass a value from the dropdownlist or IS NOT NULL (so it shows all of the values). What’s the best way to handle this? I know you can’t pass the string “IS NOT NULL” to the parameter. I’m a bit stuck on this one.

ASP.NET 3.5 and SQL Server 2008.

Answer 1

Assuming this is a stored procedure, say your parameter is called @Param1, have the parameter set to NULL to indicate IS NOT NULL, as follows:

SELECT ...
FROM   ...
WHERE  (
           (@Param1 IS NULL AND field1 IS NOT NULL)
           OR (field1 = @Param1)
       )

---

Suggested by GSerg

Testing ISNULL(@Param1, field1) = field1 with the following:

DECLARE  @test1 nvarchar(10) = 'testing',
         @test2 nvarchar(10) = NULL; -- or 'random' or 'testing'

SELECT   1
WHERE    ISNULL(@test2, @test1) = @test1;

Computations are showing as 1 for each case. This appears to be a better solution than my original answer.