topic Re: Set analysis not working when table is empty in App Development

Set analysis not working when table is empty

dselgo_eidex — Fri, 18 Mar 2022 14:46:08 GMT

Hello,

I bug showed up in our application that I thought was a little weird. Let's say that we have the following two tables:

Table A:

KEY	YEAR
1	2022

Table B (empty):

KEY

NAME

In this app I have a listbox which generates a list of the years available for records with a certain name in Table B. Its expression is:

=aggr(only({1<B.NAME = {'Foo'}>} DISTINCT A.YEAR), A.YEAR)

Normally this works fine, but when Table B is empty it results in "2022". I would expect it to result in NULL. Just using only returns the same:

=only({1<B.NAME = {'Foo'}>} DISTINCT A.YEAR)

Just wondering why this happens and if there is an easy way around it other than using an if statement.

Re: Set analysis not working when table is empty

Digvijay_Singh — Fri, 18 Mar 2022 19:57:56 GMT

Pl check what do you see with below modification

=aggr(only({1<A.YEAR = P({<B.NAME={'Foo'}>})>} DISTINCT A.YEAR), A.YEAR)

Re: Set analysis not working when table is empty

marcus_sommer — Mon, 21 Mar 2022 11:29:00 GMT

It's not a bug else an intended behaviour respectively a side-effect. Set analysis evaluates the selection states of TRUE or FALSE which aren't available by NULL. Therefore these statements will be ignored (also if there is a none existing field specified). Of course Qlik might have been implemented any additionally logic before the evaluation to fetch such scenarios but it adds an overhead and they decided against it to speed up the performance.

- Marcus

Re: Set analysis not working when table is empty

dselgo_eidex — Tue, 29 Mar 2022 15:08:45 GMT

I get the same behavior unfortunately.

Re: Set analysis not working when table is empty

dselgo_eidex — Tue, 29 Mar 2022 15:09:36 GMT

Gotcha. Thanks for confirming this!