How to keep rows only that contain an empty cell in a certain column

Hello,

I'd like to remove rows that have an entry in a certain column and to keep those rows that have no entry in that same column. Is there a simple way to do that? I thought about the Row Filter node but I can't figure out how to define "an empty cell". 

 

Example: Lets say I have 4 columns and I want to remove each row with no entry in column_4

column_1 column_2 column_3 column_4
ABC ABCDEF ABCD CDEF
1234 123456 1234  
345 56789 4567 123456789
ABCD DEFGHI DEFG  

 

This is what I want to obtain:

column_1 column_2 column_3 column_4
1234 123456 1234  
ABCD DEFGHI DEFG  

I solved the problem myself. I just found the Rule-based Row Filter which did the job very well.

The following expression did what I wanted:

$column_4$="" => TRUE

Marking as solved.

Marking as solved.

For completion, the Row filter node has an option something like 'Only Missing Cells Match' in the default options panel (the one where you can specify wildcard patterns, number ranges etc) - that does what you were looking for.  You can choose include or exclude from the left panel.

Steve