Convert blanks to Nulls for a particular field

[wonka1234]

Is there a formula I can use to convert blanks in alteryx to null values in a field?

I believe my join isnt joining correctly due to blanks being in a field instead of nulls.

[Qiu]

@wonka1234 
If I understand your intention correctly an suppose the Field is "A"

We may use the formula as below.

If isempty([A]) then null() else [A] endif

[MarqueeCrew]

@wonka1234 ,

 while I agree in theory with @Qiu , because you said blanks I want to clarify:

"" with 0 spaces is empty

" " with any quantity of spaces is NOT empty 

so if you still have a join issue, 

IIF(IsEmpty(Trim([A])),Null(),[A])

 cheers,

 mark