Filtering for Null value in Subject line

[Bob Larimer]

Is there a way to filter for e-mails that have a blank subject line?

[Jason Hobbs]

You can search for emails with no subject using:

subject:"no subject"

...In a regular email client the subject lines will actually be blank
but in the gmail web app, null subject lines actually read "(no
subject)" so this search seems to work.

^Doogie

[Greg X Newman]

This does not work:

Mail from this User client will be displayed with a filter as described above:

User-Agent: Microsoft-Entourage/12.24.0.100205
Date: xxxx
Subject: <no subject>

but not from this one:

X-MimeOLE: Produced By Microsoft Exchange V6.5
Subject: 
Date: xxxx

So is there a way to pick up ALL e-mails that have blank or empty Subject: fields?