Utilize GMail Labels

This is one small tip I found several months ago. Today I need it, but quite forget how to use it. So, this small article is only one way to make me remember when I need to use it again in the future.

If you use GMail, and applies labels to your messages, and then you want to search all mails with certain label, you can enter into GMail's search box:

label:MyLabel

But what I need today is on the contrary. I want to find all mail messages which are not labeled by certain labels. What should I do? This is what I typed in into GMail's search box:

-label:MyLabel

It is sometimes useful too if you want to search email messages which are labeled with more than two labels. How to do it? Enter this:

label:Label1 label:Label2

Or, in more compact way

label:{Label1, Label2}

Alll of these can be combined. For example, I want to find all email messages that has LabelA and LabelB, but *not* labeled with LabelX. What I should enter into the search box?

label:{LabelA, LabelB} -label:LabelX