The Nz() function fits beautifully here. To query for no-value, your query
would look like:

SELECT * FROM YourTable WHERE Nz(SomeField," ")=" "

If the possibly-null field is numeric or date, you must make a tweak as
follows:

SELECT * FROM YourTable WHERE Nz(SomeField,0)=0

See the Nz() function in the Help for details. This will return all records
where SomeField is null, equals "", or equals " ".

HTH

Null and an empty string (aka "" are not the same thing. A space (aka " ")
is something else again.

Try: Where trim(nz([Name],"")) = ""  or (my preference) Where
Len(trim(nz([Name],""))) = 0

The nz (null-to-zero) function will cause Null values to be evaluated as if
they were "".
Similarly, the trim function will cause any " " entries to evaluate as "".

(Using Len or Trim on [Name] will generate an error if Name is Null unless
you use nz() first.)

HTH