Calculate the NULL value using a Field Calculator

Discussion created by jlaroussi on Sep 11, 2012
Latest reply on Sep 13, 2012 by jlaroussi
I have a field type string with the values of ???A???, ???B??? and ???C??? and NULL (empty string). I would like to replace selected letter values with NULL, which will be an empty string, not a string ???NULL???. I tried to use in a field calculator a Python parser:
but this did not work. I found plenty of posts how to select a NULL value, but nothing helpful on how to calculate NULL in a way that it is visible as NULL/empty string also through SQL server connection. Any ideas?