difference between null() and ''

[#1]

hello guys,

I'm trying to use NullAsValue to convert data without values to some named string, but to some field, it didn't work until I use express like below to create a substitue field. my question is does QV create "blank value"(here is '') other than Null() during my JOIN, or my source data base contains "blank value", and how should I tell when NullAsValue can totally work before I try on checking the existence of "blank value".

If(*fieldname='','no value, fieldname)

thank you.

Jia Junqing

[#2]

you can use it in scripting. if(len(fieldname)=0,'no-value',fieldname) as fieldname

[#3]

Thank you guys! your notes really give me comprehensive view of null() and ''.

[oknotsen]

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