sql - Rails: Has many through associations -- find with AND condition, not OR condition -

i have following query method in activerecord model:

def self.tagged_with( string )     array = string.split(',').map{ |s| s.lstrip }     select('distinct photos.*').joins(:tags).where('tags.name' => array ) end 

so, finds records have tags taken comma separated list , converted array.

currently matches records matching tags -- how can make work matches tags.

ie: if if input: "blue, red" records tagged blue or red.

i want match records tagged blue , red.

suggestions?

-- edit --

my models so:

class photo < activerecord::base   ...   has_many :taggings, :dependent => :destroy   has_many :tags, :through => :taggings   ...   def self.tagged_with( string )     array = string.split(',').map{ |s| s.lstrip }     select('distinct photos.*').joins(:tags).where('tags.name' => array )   end   ... end  class tag < activerecord::base   has_many :taggings, :dependent => :destroy   has_many :photos, :through => :taggings end  class tagging < activerecord::base   belongs_to :photo   belongs_to :tag end 

a tag has 2 attributes: id , name (string).

this should work:

def self.tagged_with( string )   array = string.split(',').map{ |s| s.lstrip }   select('distinct photos.*').     joins(:tags).     where('tags.name' => array).     group("photos.id").     having("count(*) = #{array.size}") end 

above match photos have tags red , blue at least. means if photo has red, blue and green tags, photo match too.