mongodb query subset of an array

Question

I have a field _keywords which is an array of strings. I want to get documents of which _keywords are super-set of the query array.

For example

Answer 1

Use the $all operator:

db.article.find( { _keywords: { $all: [ 'foo1', 'foo2' ] } } );

Source: http://www.mongodb.org/display/DOCS/Advanced+Queries#AdvancedQueries-%24all