topic Re: Test if null in Expression in QlikView

Test if null in Expression

djbloiss — Wed, 25 Nov 2020 16:16:04 GMT

I am passing Variables to my expression and I want to test if the value is null, so I can do something different depending on if it is Null or not. How can I test if the variable is null? This is currently what I am testing:

if(IsNull('$1'),'Null','Not Null')

then I am calling it like this:

$(Testing($(Test)))

or this:

$(Testing)

In either case it is returning Not Null.

Re: Test if null in Expression

marcus_sommer — Mon, 15 Jan 2018 15:51:11 GMT

Try it with: if(len(trim('$1'))=0,'Null','Not Null')

- Marcus

Re: Test if null in Expression

Anil_Babu_Samineni — Mon, 15 Jan 2018 15:51:36 GMT

What does the $1 parameter contains?

Re: Test if null in Expression

djbloiss — Mon, 15 Jan 2018 15:59:04 GMT

I tell you in the original question

Re: Test if null in Expression

djbloiss — Mon, 15 Jan 2018 16:01:04 GMT

It did the same thing.

I even tried if(IsNull(trim('$1')),'Null','Not Null')

still the same result

Re: Test if null in Expression

marcus_sommer — Mon, 15 Jan 2018 16:25:57 GMT

Please provide some more details what do you want to do. I assume that you want to nest parametrized variables. This is in general possible but not trivial from a syntax point of view:

- Marcus

Re: Test if null in Expression

djbloiss — Mon, 15 Jan 2018 19:53:09 GMT

Marcus, I don't want the full answer because I am new and I am trying to figure things out on my own. Getting the full answer will not help me much.

Re: Test if null in Expression

Anil_Babu_Samineni — Tue, 16 Jan 2018 01:59:58 GMT

Can you post image of your parameters?

Re: Test if null in Expression

djbloiss — Tue, 16 Jan 2018 13:36:28 GMT

I have it figured out and am going to do a full Blog Post as this took a lot of research.