how do you search for blanks?

[twowheeler]

I hope this is not too obvious, but I have searched the site for clues already.  When using 'find a contact' how do I search for records where a field is blank?  Specifically, the street address field.  The search builder won't take ("").

Thanks.

[Donald Lobo]

actually if u leave the value field empty it does search for the empty string ('').  however we currently dont support 'is null' and 'is not null'. there is a difference between the two in standard sql. We hope to expand search builder functionality in the 2.x version of civicrm

lobo