Program indicator filter

Dear dev,

In DHIS2 version 2.22 R.22085

I want to create a program filter to count all tracked entity instances (TEI) that have not have not came to the follow up by monthly.

For example: a TEI came to the first event in May, then this TEI will not came in June and July, he/she will came on August.

I create a program indicator to count TEI with filter if all data elements of Follow-up stage is empty. I try some things like this in the filter:

#{wm3SAR4i8NV.R0lmCKv4yOE} == ‘’ and #{wm3SAR4i8NV.rEQiomK09c1} == ‘’

but it seems doesn’t work.

What is the correct way to filter if these data element is null or empty?



Le Hong Em
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