diff --git a/.gitignore b/.gitignore
index 73633ee..1b861d7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 pkg/**
+.*.swp
 smql.gemspec
diff --git a/TODO b/TODO
index 28c5c5c..e2a2eb8 100644
--- a/TODO
+++ b/TODO
@@ -1 +1,3 @@
 1) gem-plugin
+2) deprecated-warnings rails 3.1:
+	* DEPRECATION WARNING: primary_key_name is deprecated and will be removed from Rails 3.2 (use foreign_key instead).
diff --git a/VERSION b/VERSION
index 4e379d2..5a5831a 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.0.2
+0.0.7
diff --git a/lib/smql_to_ar.rb b/lib/smql_to_ar.rb
index 63e1a10..702c554 100644
--- a/lib/smql_to_ar.rb
+++ b/lib/smql_to_ar.rb
@@ -15,6 +15,18 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 class SmqlToAR
+	module Assertion
+		def raise_unless cond, exception = nil, *args
+			cond, exception, *args = yield. cond, exception, *args  if block_given?
+			raise exception || Exception, *args  unless cond
+		end
+
+		def raise_if cond, exception = nil, *args
+			cond, exception, *args = yield. cond, exception, *args  if block_given?
+			raise exception || Exception, *args  if cond
+		end
+	end
+
 	include ActiveSupport::Benchmarkable
 	############################################################################r
 	# Exceptions
@@ -31,9 +43,9 @@ class SmqlToAR
 	# Die eigentliche Exception wird in @data[:exception] hinterlegt.
 	class SubSMQLError < SMQLError
 		def initialize query, model, exception
-			ex = {:class => exception.class, :message => exception.message}
+			ex = {class: exception.class, message: exception.message}
 			ex[:data] = exception.data  if exception.respond_to? :data
-			super :query => query, :model => model.to_s, :exception => ex
+			super query: query, model: model.to_s, exception: ex
 			set_backtrace exception.backtrace
 		end
  	end
@@ -43,43 +55,49 @@ class SmqlToAR
 	# Malformed ColOp
 	class UnexpectedColOpError < ParseError
 		def initialize model, colop, val
-			super :got => colop, :val => val, :model => model.to_s
+			super got: colop, val: val, model: model.to_s
 		end
 	end
 
 	class UnexpectedError < ParseError
 		def initialize model, colop, val
-			super :got => {colop => val}, :model => model.to_s
+			super got: {colop => val}, model: model.to_s
 		end
 	end
 
 	class NonExistingSelectableError < SMQLError
 		def initialize got
-			super :got => got
+			super got: got
 		end
 	end
 
 	class NonExistingColumnError < SMQLError
 		def initialize expected, got
-			super :expected => expected, :got => got
+			super expected: expected, got: got
 		end
 	end
 
 	class NonExistingRelationError < SMQLError
 		def initialize expected, got
-			super :expected => expected, :got => got
+			super expected: expected, got: got
 		end
 	end
 
 	class ProtectedColumnError < SMQLError
 		def initialize protected_column
-			super :protected_column => protected_column
+			super protected_column: protected_column
 		end
  	end
 
-	class OnlyOrderOnBaseError < SMQLError
+	class RootOnlyFunctionError < SMQLError
 		def initialize path
-			super :path => path
+			super path: path
+		end
+	end
+
+	class ConColumnError < SMQLError
+		def initialize expected, got
+			super expected: expected, got: got
 		end
 	end
 
@@ -89,7 +107,8 @@ class SmqlToAR
 
 	# Model der Relation `rel` von `model`
 	def self.model_of model, rel
-		model.reflections[ rel.to_sym].andand.klass
+		r = model.reflections[ rel.to_sym].andand.klass
+		r.nil? && rel === :self ? model : r
 	end
 
 	# Eine Spalte in einer Tabelle, relativ zu `Column#model`.
@@ -100,10 +119,43 @@ class SmqlToAR
 		attr_reader :path, :col
 		attr_accessor :model
 
+		class Col
+			include Comparable
+			attr_accessor :col, :as
+			def initialize col, as = nil
+				if col.kind_of? Col
+					@col, @as = col.col, col.as
+				elsif /^(.*?)\[(.*)\]$/ =~ col.to_s
+					@col, @as = $1, $2
+				else
+					@col, @as = col.to_s, as.to_s
+					@as = nil  if @as.blank?
+				end
+			end
+
+			def to_s()  @col  end
+			def to_sym()  to_s.to_sym  end
+			def inspect()  "#{@col}[@#{@as}]"  end
+			def to_alias()  "#{@col}[#{@as}]"  end
+
+			def == other
+				other = Col.new other
+				@col == other.col  &&  @as == other.as
+			end
+
+			def === other
+				@col == Col.new( other).col
+			end
+		end
+
 		def initialize model, *col
 			@model = model
 			@last_model = nil
-			*@path, @col = Array.wrap( col).collect {|s| s.to_s.split /[.\/]/ }.flatten.collect &:to_sym
+			*@path, @col = *Array.wrap( col).
+					collect {|x| x.to_s.split /[.\/]/ }.
+					flatten.
+					collect( &Col.method( :new)).
+					reject {|x| x === :self }
 		end
 
 		def last_model
@@ -113,9 +165,11 @@ class SmqlToAR
 		def each
 			model = @model
 			@path.each do |rel|
-				model = SmqlToAR.model_of model, rel
-				return false  unless model
-				yield rel, model
+				unless rel === :self
+					model = SmqlToAR.model_of model, rel
+					return false  unless model
+					yield rel, model
+				end
 			end
 			model
 		end
@@ -140,19 +194,24 @@ class SmqlToAR
 		def joins builder = nil, table = nil, &exe
 			pp = []
 			table = Array.wrap table
-			exe ||= builder ? lambda {|j, m| builder.join table+j, m} : Array.method( :[])
+			exe ||= builder ? lambda {|j, m| builder.joins table+j, m} : Array.method( :[])
 			collect do |rel, model|
 				pp.push rel
 				exe.call pp, model
 			end
 	 	end
-		def to_a()   @path+[@col]  end
+
+		def self?()  !@col  end
+		def length() @path.length+(self.self? ? 0 : 1)  end
+		def size()   @path.size+(self.self? ? 0 : 1)  end
+		def to_a()   @path+(self.self? ? [] : [@col])  end
 		def to_s()   to_a.join '.'  end
 		def to_sym() to_s.to_sym  end
 		def to_json()  to_s  end
 		def inspect()  "#<Column: #{model} #{to_s}>"  end
-		def relation()  SmqlToAR.model_of last_model, @col  end
+		def relation()  self.self? ? model : SmqlToAR.model_of( last_model, @col)  end
 		def allowed?()  ! self.protected?  end
+		def child?()  @path.empty? and !!relation  end
 	end
 
 	attr_reader :model, :query, :conditions, :builder, :order
@@ -163,10 +222,8 @@ class SmqlToAR
 				SmqlToAR.logger = ::Rails.logger
 			end
 		end
-	else
-		require 'logger'
-		@@logger = Logger.new $stdout
 	end
+	@@logger = ::Rails.logger || begin require 'logger'; Logger.new( $stdout) end
 
 	class <<self
 		def logger=(logger)  @@logger = logger  end
@@ -179,39 +236,83 @@ class SmqlToAR
 		#p model: @model, query: @query
 	end
 
-	def parse
-		benchmark 'SMQL parse' do
-			@conditions = ConditionTypes.try_parse @model, @query
+	def self.models models
+		models = Array.wrap models
+		r = Hash.new {|h,k| h[k] = {} }
+		while model = models.tap( &:uniq!).pop
+			refls = model.respond_to?( :reflections) && model.reflections
+			refls && refls.each do |name, refl|
+				r[model.name][name] = case refl
+					when ActiveRecord::Reflection::ThroughReflection then {macro: refl.macro, model: refl.klass.name, through: refl.through_reflection.name}
+					when ActiveRecord::Reflection::AssociationReflection then {macro: refl.macro, model: refl.klass.name}
+					else raise "Ups: #{refl.class}"
+					end
+				models.push refl.klass  unless r.keys.include? refl.klass.name
+			end
 		end
+		r
+	end
+
+	def parse
+		#benchmark 'SMQL parse' do
+			@conditions = ConditionTypes.try_parse @model, @query
+		#end
 		#p conditions: @conditions
 		self
 	end
 
 	def build
-		benchmark 'SMQL build query' do
+		#benchmark 'SMQL build query' do
 			@builder = QueryBuilder.new @model
 			table = @builder.base_table
 			@conditions.each {|condition| condition.build builder, table }
-		end
+		#end
 		#p builder: @builder
 		self
 	end
 
 	def ar
-		@ar ||= benchmark 'SMQL ar' do
+		@ar ||= #benchmark 'SMQL ar' do
 			@builder.to_ar
-		end
+		#end
 	end
 
 	def to_ar
-		benchmark 'SMQL' do
+		#benchmark 'SMQL' do
 			parse
 			build
 			ar
-		end
+		#end
 	end
 
 	def self.to_ar *params
 		new( *params).to_ar
 	end
+
+	def self.reload_library
+		lib_dir = File.dirname __FILE__
+		fj = lambda {|*a| File.join lib_dir, *a }
+		Object.send :remove_const, :SmqlToAR
+		load fj[ 'smql_to_ar.rb']
+		load fj[ 'smql_to_ar', 'condition_types.rb']
+		load fj[ 'smql_to_ar', 'query_builder.rb']
+	end
+
+	module ActiveRecordExtensions
+		def self.included base
+			base.extend ClassMethods
+		end
+
+		module ClassMethods
+			def smql *params
+				SmqlToAR.to_ar self, *params
+			end
+
+			def smql_protected
+				[]
+			end
+		end
+	end
 end
+
+ActiveRecord::Base.send :include, SmqlToAR::ActiveRecordExtensions
diff --git a/lib/smql_to_ar/condition_types.rb b/lib/smql_to_ar/condition_types.rb
index bcf21cb..548cd89 100644
--- a/lib/smql_to_ar/condition_types.rb
+++ b/lib/smql_to_ar/condition_types.rb
@@ -14,6 +14,9 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+# TODO:
+# * Array als Typ ist zu allgemein. Allgemeine Lösung gesucht, um die Typen im Array angeben zu können.
+
 class SmqlToAR
 	#############################################################################
 	# Alle Subklassen (qualitativ: ConditionTypes::*), die als Superklasse Condition haben,
@@ -25,28 +28,44 @@ class SmqlToAR
 	# Nimmt eine Klasse ein Objekt an,  so soll diese Klasse instanziert werden.
 	# Alles weitere siehe Condition.
 	module ConditionTypes
+		extend SmqlToAR::Assertion
+
 		class <<self
 			# Ex: 'givenname|surname|nick' => [:givenname, :surname, :nick]
 			def split_keys k
 				k.split( '|').collect &:to_sym
 			end
 
+			def conditions &e
+				unless block_given?
+					r = Enumerator.new( self, :conditions)
+					s = self
+					r.define_singleton_method :[] do |k|
+						s.conditions.select {|c| c::Operator === k }
+					end
+					return r
+				end
+				constants.each do |c|
+					next  if :Condition == c
+					c = const_get c
+					next  if Condition === c
+					yield c
+				end
+			end
+
 			# Eine Regel parsen.
 			# Ex: Person, "givenname=", "Peter"
 			def try_parse_it model, colop, val
 				r = nil
 				#p :try_parse => { :model => model, :colop => colop, :value => val }
-				constants.each do |c|
-					next  if :Condition == c
-					c = const_get c
-					next  if Condition === c
-					raise UnexpectedColOpError.new( model, colop, val)  unless colop =~ /^(?:\d*:)?(.*?)(\W*)$/
+				conditions.each do |c|
+					raise_unless colop =~ /^(?:\d*:)?(.*?)((?:\W*(?!\])\W)?)$/, UnexpectedColOpError.new( model, colop, val)
 					col, op = $1, $2
 					col = split_keys( col).collect {|c| Column.new model, c }
 					r = c.try_parse model, col, op, val
 					break  if r
 				end
-				raise UnexpectedError.new( model, colop, val)  unless r
+				raise_unless r, UnexpectedError.new( model, colop, val)
 				r
 			end
 
@@ -72,19 +91,28 @@ class SmqlToAR
 		end
 
 		class Condition
+			include SmqlToAR::Assertion
+			extend SmqlToAR::Assertion
 			attr_reader :value, :cols
 			Operator = nil
 			Expected = []
 			Where = nil
 
-			# Versuche das Objekt zu erkennen.  Operator und Expected muessen passen.
-			# Passt das Object,  die Klasse instanzieren.
-			def self.try_parse model, cols, op, val
-				#p :self => name, :try_parse => op, :cols => cols, :with => self::Operator, :value => val, :expected => self::Expected, :model => model.name
-				new model, cols, val  if self::Operator === op and self::Expected.any? {|i| i === val }
+			class <<self
+				# Versuche das Objekt zu erkennen.  Operator und Expected muessen passen.
+				# Passt das Object,  die Klasse instanzieren.
+				def try_parse model, cols, op, val
+					#p :class => self, :self => name, :try_parse => op, :cols => cols, :with => self::Operator, :value => val, :expected => self::Expected, :model => model.name
+					new model, cols, val  if self::Operator === op and self::Expected.any? {|x| x === val}
+				end
+
+				def inspect
+					"#{self.name}( :operator=>#{self::Operator.inspect}, :expected=>#{self::Expected.inspect}, :where=>#{self::Where.inspect})"
+				end
 			end
 
 			def initialize model, cols, val
+				#p init: self, caller: caller
 				@model, @cols = model, cols
 				@value = case val
 					when Hash, Range then val
@@ -93,6 +121,10 @@ class SmqlToAR
 				verify
 			end
 
+			def inspect
+				"#<#{self.class.name}:0x#{(self.object_id<<1).to_s 16} model: #{self.class.name}, cols: #{@cols.inspect}, value: #{@value.inspect}>"
+			end
+
 			def verify
 				@cols.each do |col|
 					verify_column col
@@ -103,53 +135,55 @@ class SmqlToAR
 			# Gibt es eine Spalte diesen Namens?
 			# Oder:  Gibt es eine Relation diesen Namens?  (Hier nicht der Fall)
 			def verify_column col
-				raise NonExistingColumnError.new( %w[Column], col)  unless col.exist_in?
+				raise_unless col.exist_in?, NonExistingColumnError.new( %w[Column], col)
 			end
 
 			# Modelle koennen Spalten/Relationen verbieten mit Model#smql_protected.
 			# Dieses muss ein Object mit #include?( name_als_string) zurueckliefern,
 			# welches true fuer verboten und false fuer, erlaubt steht.
 			def verify_allowed col
-				raise ProtectedColumnError.new( col)  if col.protected?
+				raise_if col.protected?, ProtectedColumnError.new( col)
 			end
 
 			# Erstelle alle noetigen Klauseln. builder nimmt diese entgegen,
-			# wobei builder.join, builder.select, builder.where und builder.wobs von interesse sind.
-			# mehrere Schluessel bedeuten, dass die Values _alle_ zutreffen muessen, wobei die Schluessel geodert werden.
+			# wobei builder.joins, builder.select, builder.where und builder.wobs von interesse sind.
+			# mehrere Schluessel bedeuten, dass die Values _alle_ zutreffen muessen, wobei die Schluessel geODERt werden.
 			# Ex:
 			# 1) {"givenname=", "Peter"} #=> givenname = 'Peter'
 			# 2) {"givenname=", ["Peter", "Hans"]} #=> ( givenname = 'Peter' OR givenname = 'Hans' )
 			# 3) {"givenname|surname=", ["Peter", "Mueller"]}
 			#       #=> ( givenname = 'Peter' OR surname = 'Peter' ) AND ( givenname = 'Mueller' OR surname = 'Mueller' )
-			def build builder, table
+			def condition_build builder, table
 				values = Hash[ @value.collect {|value| [ builder.vid, value ] } ]
-				values.each {|k, v| builder.wobs k.sym => v }
+				values.each {|k, v| builder.wobs k.to_sym => v }
 				if 1 == @cols.length
 					@cols.each do |col|
 						col.joins builder, table
 						col = builder.column table+col.path, col.col
-						builder.where *values.keys.collect {|vid| self.class::Where % [ col, vid.to_s ] }
+						builder.where values.keys.collect {|vid| self.class::Where % [ col, vid.to_s ] }
 					end
 				else
+					b2 = SmqlToAR::And.new builder
 					values.keys.each do |vid|
-						builder.where *@cols.collect {|col|
+						b2.where SmqlToAR::Or[ *@cols.collect {|col|
 								col.joins builder, table
 								col = builder.column table+col.path, col.col
 								self.class::Where % [ col, vid.to_s ]
-							}
+							}]
 					end
 				end
 				self
 			end
+			alias build condition_build
 		end
 
 		class NotInRange < Condition
 			Operator = '!..'
-			Where = "%s NOT BETWEEN %s AND %s"
+			Where = '%s NOT BETWEEN %s AND %s'
 			Expected = [Range, lambda {|val| Array === val && 2 == val.length } ]
 
-			def initialze model, cols, val
-				if Array === val && 2 == val.length
+			def initialize model, cols, val
+				if Array === val
 					f, l = val
 					f, l = Time.parse(f), Time.parse(l)  if f.kind_of? String
 					val = f..l
@@ -157,23 +191,65 @@ class SmqlToAR
 				super model, cols, val
 			end
 
-			def build builder, table
-				builder.wobs (v1 = builder.vid) => @value.begin, (v2 = builder.vid) => @value.end
+			def not_in_range_build builder, table
+				builder.wobs (v1 = builder.vid).to_sym => @value.begin, (v2 = builder.vid).to_sym => @value.end
 				@cols.each do |col|
 					col.joins builder, table
 					builder.where self.class::Where % [ builder.column( table+col.path, col.col), v1, v2]
 				end
 				self
 			end
+			alias build not_in_range_build
 		end
-		InRange = simple_condition NotInRange, '..', "%s BETWEEN %s AND %s"
+		InRange = simple_condition NotInRange, '..', '%s BETWEEN %s AND %s'
+
+		# Every key-pair will be ORed.  No multiple values possible.
+		class Overlaps < Condition
+			Operator, Where = '<=>', '(%s, %s) OVERLAPS (%s, %s)'
+			Expected = [Range, lambda {|val|
+					Array === val && 2 == val.length &&
+						[Time, Date, String].any? {|v|v===val[0]} &&
+						[Numeric, String].any? {|v|v===val[1]}
+				}]
+
+			def initialize model, cols, val
+				if Array === val
+					f = Time.parse( val[0]).localtime
+					l = val[1]
+					l = case l
+						when String then Time.parse( l).localtime
+						when Numeric then f+l
+						else raise ArgumentError, "Unexpected type for end-value #{l.inspect}"
+						end
+					f += f.utc_offset
+					l += l.utc_offset
+					val = f.utc..l.utc
+				end
+				super model, cols, val
+			end
+
+			def overlaps_build builder, table
+				builder = Or.new builder
+				builder.wobs (v1 = builder.vid).to_sym => @value.begin, (v2 = builder.vid).to_sym => @value.end
+				v1 = "TIMESTAMP #{v1}"
+				v2 = "TIMESTAMP #{v2}"
+				@cols.each do |col|
+					col.joins builder, table
+				end.each_slice 2 do |f,s|
+					builder.where self.class::Where % [
+						builder.column( table+f.path, f.col), builder.column( table+s.path, s.col), v1, v2]
+				end
+			end
+			alias build overlaps_build
+		end
+		NotOverlaps = simple_condition Overlaps, '<=>', 'NOT (%s, %s) OVERLAPS (%s, %s)'
 
 		class NotIn < Condition
 			Operator = '!|='
 			Where = "%s NOT IN (%s)"
 			Expected = [Array]
 
-			def build builder, table
+			def not_in_build builder, table
 				builder.wobs (v = builder.vid).to_sym => @value
 				@cols.each do |col|
 					col.joins builder, table
@@ -181,54 +257,119 @@ class SmqlToAR
 				end
 				self
 			end
+			alias build not_in_build
 		end
 
 		In = simple_condition NotIn, '|=', '%s IN (%s)', [Array]
 		In2 = simple_condition In, '', nil, [Array]
-		NotEqual = simple_condition Condition, /\!=|<>/, "%s <> %s", [Array, String, Numeric]
+		NotEqual = simple_condition Condition, '!=', "%s <> %s", [Array, String, Numeric]
+		NotEqual2 = simple_condition Condition, '<>', "%s <> %s", [Array, String, Numeric]
 		GreaterThanOrEqual = simple_condition Condition, '>=', "%s >= %s", [Array, Numeric]
 		LesserThanOrEqual = simple_condition Condition, '<=', "%s <= %s", [Array, Numeric]
+		class StringTimeGreaterThanOrEqual < Condition
+			Operator, Where, Expected = '>=', '%s >= %s', [Time, Date, String]
+			def initialize model, cols, val
+				super model, cols, Time.parse( val.to_s)
+			end
+		end
+		StringTimeLesserThanOrEqual = simple_condition StringTimeGreaterThanOrEqual, '<=', "%s <= %s"
+
+		# Examples:
+		# { 'articles=>' => { id: 1 } }
+		# { 'articles=>' => [ { id: 1 }, { id: 2 } ] }
 		class EqualJoin <Condition
-			Operator = '='
-			Expected = [Hash]
+			Operator = '=>'
+			Expected = [Hash, lambda {|x| x.kind_of?( Array) and x.all? {|y| y.kind_of?( Hash) }}]
 
 			def initialize *pars
 				super( *pars)
+				@value = Array.wrap @value
 				cols = {}
 				@cols.each do |col|
-					col_model = SmqlToAR.model_of col.last_model, col.col
-					#p col_model: col_model.to_s, value: @value
-					cols[col] = [col_model] + ConditionTypes.try_parse( col_model, @value)
+					col_model = col.relation
+					cols[col] = [col_model] + @value.collect {|val| ConditionTypes.try_parse( col_model, val) }
 				end
 				@cols = cols
 			end
 
 			def verify_column col
-				refl = SmqlToAR.model_of col.last_model, col.col
-				#p refl: refl, model: @model.name, col: col, :reflections => @model.reflections.keys
-				raise NonExistingRelationError.new( %w[Relation], col)  unless refl
+				raise_unless col.relation, NonExistingRelationError.new( %w[Relation], col)
 			end
 
-			def build builder, table
+			def equal_join_build builder, table
+				if 2 < @cols.first.second.length
+					b2, b3 = And, Or
+				else
+					b2, b3 = Or, And
+				end
+				b2 = b2.new builder
 				@cols.each do |col, sub|
+					model, *sub = sub
 					t = table + col.path + [col.col]
-					#p sub: sub
-					p col: col, joins: col.joins
-					col.joins.each {|j, m| builder.join table+j, m }
-					builder.join t, SmqlToAR.model_of( col.last_model, col.col)
-					sub[1..-1].each {|one| one.build builder, t }
+					col.joins builder, table
+					builder.joins t, model
+					b4 = b3.new( b2)
+					sub.each do |i|
+						b5 = And.new b4
+						i.collect {|j| j.build b5, t }
+					end
 				end
 				self
 			end
+			alias build equal_join_build
 		end
-		Equal = simple_condition Condition, '=', "%s = %s", [Array, String, Numeric]
-		Equal2 = simple_condition Equal, '', "%s = %s", [String, Numeric]
+
+		# Takes to Queries.
+		# First Query will be a Subquery, second a regular query.
+		# Example:
+		#   Person.smql 'sub.articles:' => [{'limit:' => 1, 'order:': 'updated_at desc'}, {'content~' => 'some text'}]
+		# Person must have as last Article (compared by updated_at) owned by Person a Artive which has 'some text' in content.
+		# The last Article needn't to have 'some text' has content,  the subquery takes it anyway.
+		# But the second query compares to it and never to any other Article,  because these are filtered by first query.
+		# The difference to
+		#   Person.smql :articles => {'content~' => 'some text', 'limit:' => 1, 'order:': 'updated_at desc'}
+		# is,  second is not allowed (limit and order must be in root) and this means something like
+		#   "Person must have the Article owned by Person which has 'some text' in content.
+		#   limit and order has no function in this query and this article needn't to be the last."
+=begin
+		class SubEqualJoin < EqualJoin
+			Operator = '()'
+			Expected = [lambda {|x| x.kind_of?( Array) and (1..2).include?( x.length) and x.all?( &it.kind_of?( Hash))}]
+
+			def initialize model, cols, val
+				super model, cols, val[1]
+				# sub: model, subquery, sub(condition)
+				@cols.each {|col, sub| sub[ 1..-1] = SmqlToAR.new( col.relation, val[0]).parse, *sub[-1] }
+			end
+
+			def verify_column col
+				raise_unless col.child?, ConColumnError.new( [:Column], col)
+			end
+
+			def sub_equal_join_build builder, table
+				@cols.each do |col, sub|
+					t = table+col.to_a
+					builder.sub_joins t, col, *sub[0..1]
+					#ap sub: sub[2..-1]
+					sub[2..-1].each {|x| x.build builder, t }
+				end
+				self
+			end
+			alias build sub_equal_join_build
+		end
+=end
+
+		Equal = simple_condition Condition, '=', "%s = %s", [Array, String, Numeric, Date, Time]
+		Equal2 = simple_condition Equal, '', "%s = %s", [String, Numeric, Date, Time]
 		GreaterThan = simple_condition Condition, '>', "%s > %s", [Array, Numeric]
+		StringTimeGreaterThan = simple_condition StringTimeGreaterThanOrEqual, '>', "%s > %s"
 		LesserThan = simple_condition Condition, '<', "%s < %s", [Array, Numeric]
+		StringTimeLesserThan = simple_condition StringTimeGreaterThanOrEqual, '<', "%s < %s"
 		NotIlike = simple_condition Condition, '!~', "%s NOT ILIKE %s", [Array, String]
 		Ilike = simple_condition Condition, '~', "%s ILIKE %s", [Array, String]
+		Exists = simple_condition Condition, '', '%s IS NOT NULL', [TrueClass]
+		NotExists = simple_condition Condition, '', '%s IS NULL', [FalseClass]
 
-		####### No Operator #######
 		Join = simple_condition EqualJoin, '', nil, [Hash]
 		InRange2 = simple_condition InRange, '', nil, [Range]
 		class Select < Condition
@@ -236,10 +377,10 @@ class SmqlToAR
 			Expected = [nil]
 
 			def verify_column col
-				raise NonExistingSelectableError.new( col)  unless col.exist_in? or SmqlToAR.model_of( col.last_model, col.col)
+				raise_unless col.exist_in? || SmqlToAR.model_of( col.last_model, col.col), NonExistingSelectableError.new( col)
 			end
 
-			def build builder, table
+			def select_build builder, table
 				@cols.each do |col|
 					if col.exist_in?
 						col.joins builder, table
@@ -251,6 +392,7 @@ class SmqlToAR
 				end
 				self
 			end
+			alias build select_build
 		end
 
 		class Functions < Condition
@@ -258,13 +400,19 @@ class SmqlToAR
 			Expected = [String, Array, Hash, Numeric, nil]
 
 			class Function
+				include SmqlToAR::Assertion
 				Name = nil
 				Expected = []
 				attr_reader :model, :func, :args
 
-				def self.try_parse model, func, args
-					SmqlToAR.logger.info( { try_parse: [func,args]}.inspect)
-					self.new model, func, args  if self::Name === func and self::Expected.any? {|e| e === args }
+				class <<self
+					def try_parse model, func, args
+						self.new model, func, args  if self::Name === func and self::Expected.any? {|x| x === args }
+					end
+
+					def inspect
+						"#{self.name}( :name=>#{self::Name}, :expected=>#{self::Expected})"
+					end
 				end
 
 				def initialize model, func, args
@@ -277,47 +425,64 @@ class SmqlToAR
 				Expected = [String, Array, Hash, nil]
 
 				def initialize model, func, args
-					SmqlToAR.logger.info( {args: args}.inspect)
 					args = case args
 						when String then [args]
 						when Array, Hash then args.to_a
 						when nil then nil
 						else raise 'Oops'
 						end
-					SmqlToAR.logger.info( {args: args}.inspect)
 					args.andand.collect! do |o|
 						o = Array.wrap o
 						col = Column.new model, o.first
 						o = 'desc' == o.last.to_s.downcase ? :DESC : :ASC
-						raise NonExistingColumnError.new( [:Column], col)  unless col.exist_in?
+						raise_unless col.exist_in?, NonExistingColumnError.new( [:Column], col)
 						[col, o]
 					end
-					SmqlToAR.logger.info( {args: args}.inspect)
 					super model, func, args
 				end
 
-				def build builder, table
+				def order_build builder, table
 					return  if @args.blank?
 					@args.each do |o|
 						col, o = o
 						col.joins builder, table
 						t = table + col.path
-						#raise OnlyOrderOnBaseError.new( t)  unless 1 == t.length
+						#raise_unless 1 == t.length, RootOnlyFunctionError.new( t)
 						builder.order t, col.col, o
 					end
 				end
+				alias build order_build
+			end
+
+			class Limit < Function
+				Name = :limit
+				Expected = [Fixnum]
+
+				def limit_build builder, table
+					raise_unless 1 == table.length, RootOnlyFunctionError.new( table)
+					builder.limit = Array.wrap(@args).first.to_i
+				end
+				alias build limit_build
+			end
+
+			class Offset < Function
+				Name = :offset
+				Expected = [Fixnum]
+
+				def offset_build builder, table
+					raise_unless 1 == table.length, RootOnlyFunctionError.new( table)
+					builder.offset = Array.wrap(@args).first.to_i
+				end
+				alias build offset_build
 			end
 
 			def self.new model, col, val
-				SmqlToAR.logger.info( { function: col.first.to_sym }.inspect)
 				r = nil
 				constants.each do |c|
 					next  if [:Function, :Where, :Expected, :Operator].include? c
 					c = const_get c
 					next  if Function === c or not c.respond_to?( :try_parse)
-					SmqlToAR.logger.info( {f: c}.inspect)
 					r = c.try_parse model, col.first.to_sym, val
-					SmqlToAR.logger.info( {r: r}.inspect)
 					break  if r
 				end
 				r
diff --git a/lib/smql_to_ar/query_builder.rb b/lib/smql_to_ar/query_builder.rb
index 0eb06a5..4e8ad3c 100644
--- a/lib/smql_to_ar/query_builder.rb
+++ b/lib/smql_to_ar/query_builder.rb
@@ -22,36 +22,74 @@ class SmqlToAR
 		class Vid
 			attr_reader :vid
 			def initialize( vid)  @vid = vid  end
-			def to_s() ":c#{@vid}" end
-			def to_sym() "c#{@vid}".to_sym end
+			def to_s() ":smql_c#{@vid}" end
+			def to_sym() "smql_c#{@vid}".to_sym end
 			alias sym to_sym
 			def to_i()  @vid  end
+			def === other
+				to_s === other || to_sym === other || to_i === other || self == other || self === other
+			end
 		end
 
-		attr_reader :table_alias, :model, :table_model, :base_table, :_where, :_select, :_wobs, :_joins
-		attr_accessor :logger
+		class Aliases < Hash
+			attr_accessor :counter, :prefix
 
-		def initialize model
-			@logger = SmqlToAR.logger
-			@table_alias = Hash.new do |h, k|
-				k = Array.wrap k
-				h[k] = "smql,#{k.join(',')}"
+			def initialize prefix, *a, &e
+				@counter, @prefix = 0, prefix || 'smql'
+				super *a, &e
 			end
-			@_vid, @_where, @_wobs, @model, @quoter = 0, [], {}, model, model.connection
-			@base_table = [model.table_name.to_sym]
+
+			def format name
+				pre, suf = name.split( ',', 2)
+				return name  unless suf
+				pre += ",#{@counter += 1},"
+				l = 60-pre.length
+				n = suf[(suf.length<=l ? 0 : -l)..-1]
+				n == suf ? pre+n : "#{pre},,,#{n}"
+			end
+
+			def name n
+				n.collect( &:to_alias).join ','
+			end
+
+			def [] k
+				n = name k
+				v = super n
+				v = self[k] = format( "#{prefix},#{n}")  unless v
+				v
+			end
+
+			def []= k, v
+				super name( k), v
+			end
+		end
+
+		attr_reader :table_alias, :model, :table_model, :base_table, :_where, :_select, :_wobs, :_joins, :prefix, :_vid
+		attr_accessor :logger, :limit, :offset
+
+		def initialize model, prefix = nil
+			@prefix = "smql"
+			@logger = SmqlToAR.logger
+			@table_alias = Aliases.new @prefix
+			@_vid, @_where, @_wobs, @model, @quote = 0, SmqlToAR::And[], {}, model, model.connection
+			@base_table = [Column::Col.new( model.table_name)]
 			@table_alias[ @base_table] = @base_table.first
-			t = quote_table_name @table_alias[ @base_table]
-			@_select, @_joins, @_joined, @_includes, @_order = ["DISTINCT #{t}.*"], "", [], [], []
+			t = quote_table_name @base_table.first.col
+			@_select, @_joins, @_joined, @_includes, @_order = ["DISTINCT #{t}.*"], "", [@base_table], [], []
 			@table_model = {@base_table => @model}
 		end
 
 		def vid()  Vid.new( @_vid+=1)  end
 
+		def inspect
+			"#<#{self.class.name}:#{"0x%x"% (self.object_id<<1)}|#{@prefix}:#{@base_table}:#{@model} vid=#{@_vid} where=#{@_where} wobs=#{@_wobs} select=#{@_select} aliases=#{@table_alias}>"
+		end
+
 		# Jede via where uebergebene Condition wird geodert und alle zusammen werden geundet.
 		# "Konjunktive Normalform".  Allerdings duerfen Conditions auch Komplexe Abfragen enthalten.
-		# Ex: builder.where( 'a = a', 'b = c').where( 'c = d', 'e = e').where( 'x = y').where( '( m = n AND o = p )', 'f = g')
+		# Ex: builder.where( ['a = a', 'b = c']).where( ['c = d', 'e = e']).where( 'x = y').where( ['( m = n AND o = p )', 'f = g'])
 		#        #=> WHERE ( a = a OR b = c ) AND ( c = d OR e = e ) AND x = y ( ( m = n AND o = p ) OR f = g )
-		def where *cond
+		def where cond
 			@_where.push cond
 			self
 		end
@@ -62,44 +100,71 @@ class SmqlToAR
 		end
 
 		def quote_column_name name
-			@quoter.quote_column_name( name).gsub /"\."/, ','
+			@quote.quote_column_name( name).gsub /"\."/, ','
 		end
 
 		def quote_table_name name
-			@quoter.quote_table_name( name).gsub /"\."/, ','
+			name = case name
+				when Array, Column::Col then @table_alias[Array.wrap name]
+				else name.to_s
+				end
+			@quote.quote_table_name name
 		end
 
 		def column table, name
-			"#{quote_table_name table.kind_of?(String) ? table : @table_alias[table]}.#{quote_column_name name}"
+			"#{quote_table_name table}.#{quote_column_name name}"
 		end
 
 		def build_join orig, pretable, table, prekey, key
-			" JOIN #{quote_table_name orig.to_sym} AS #{quote_table_name table} ON #{column pretable, prekey} = #{column table, key} "
+			"\tLEFT JOIN #{orig} AS #{quote_table_name table}\n\tON #{column pretable, prekey} = #{column table, key}\n"
 		end
 
-		def join table, model
-			return self  if @_joined.include? table # Already joined
-			pretable = table[0...-1]
+		def sub_joins table, col, model, query
+			prefix, base_table = "#{@prefix}_sub", col.relation.table_name
+			join_ table, model, "(#{query.build( prefix).ar.to_sql})"
+		end
+
+		def join_ table, model, query, pretable = nil
+			pretable ||= table[0...-1]
 			@table_model[ table] = model
-			premodel = @table_model[ pretable]
+			@table_model.rehash
+			premodel = @table_model.find {|k,v| pretable == k }[1]
 			t = @table_alias[ table]
-			pt = quote_table_name @table_alias[ table[ 0...-1]]
-			refl = premodel.reflections[table.last]
-			case refl.macro
-			when :has_many
-				@_joins += build_join model.table_name, pretable, t, premodel.primary_key, refl.primary_key_name
-			when :belongs_to
-				@_joins += build_join model.table_name, pretable, t, refl.primary_key_name, premodel.primary_key
-			when :has_and_belongs_to_many
-				jointable = [','] + table
-				@_joins += build_join refl.options[:join_table], pretable, @table_alias[jointable], premodel.primary_key, refl.primary_key_name
-				@_joins += build_join model.table_name, jointable, t, refl.association_foreign_key, refl.association_primary_key
-			else raise BuilderError, "Unkown reflection macro: #{refl.macro.inspect}"
+			pt = quote_table_name table[ 0...-1]
+			refl = premodel.reflections[table.last.to_sym]
+			case refl
+			when ActiveRecord::Reflection::ThroughReflection
+				through = refl.through_reflection
+				through_table = table[0...-1]+[Column::Col.new( through.name, table.last.as)]
+				srctable = through_table+[Column::Col.new( refl.source_reflection.name, table.last.as)]
+				@table_model[ srctable] = model
+				@table_alias[ table] = @table_alias[ srctable]
+				join_ through_table, through.klass, quote_table_name( through.table_name)
+				join_ srctable, refl.klass, query, through_table
+			when ActiveRecord::Reflection::AssociationReflection
+				case refl.macro
+				when :has_many, :has_one
+					@_joins += build_join query, pretable, t, premodel.primary_key, refl.foreign_key
+				when :belongs_to
+					@_joins += build_join query, pretable, t, refl.foreign_key, premodel.primary_key
+				when :has_and_belongs_to_many
+					jointable = [Column::Col.new(',')] + table
+					@_joins += build_join refl.options[:join_table], pretable, @table_alias[ jointable], premodel.primary_key, refl.foreign_key
+					@_joins += build_join query, jointable, t, refl.association_foreign_key, refl.association_primary_key
+				else raise BuilderError, "Unkown reflection macro: #{refl.macro.inspect}"
+				end
+			else raise BuilderError, "Unkown reflection type: #{refl.class.name} #{refl.macro.inspect}"
 			end
-			@_joined.push table
 			self
 		end
 
+		def joins table, model
+			table = table.flatten.compact
+			return self  if @_joined.include? table # Already joined
+			join_ table, model, quote_table_name( model.table_name)
+			@_joined.push table
+		end
+
 		def includes table
 			@_includes.push table
 			self
@@ -111,36 +176,28 @@ class SmqlToAR
 		end
 
 		def order table, col, o
-			tc = column table, col
+			ct = column table, col
 			@_select.push ct
 			@_order.push "#{ct} #{:DESC == o ? :DESC : :ASC}"
 			self
 		end
 
-		class Dummy
-			def method_missing m, *a, &e
-				#p :dummy => m, :pars => a, :block => e
-				self
-			end
-		end
-
 		def build_ar
-			where_str = @_where.collect do |w|
-				w = Array.wrap w
-				1 == w.length ? w.first : "( #{w.join( ' OR ')} )"
-			end.join ' AND '
+			where_str = @_where.type_correction!.optimize!.build_where
 			incls = {}
 			@_includes.each do |inc|
 				b = incls
 				inc[1..-1].collect {|rel| b = b[rel] ||= {} }
 			end
-			@logger.debug incls: incls, joins: @_joins
 			@model = @model.
 				select( @_select.join( ', ')).
 				joins( @_joins).
 				where( where_str, @_wobs).
 				order( @_order.join( ', ')).
 				includes( incls)
+			@model = @model.limit @limit  if @limit
+			@model = @model.offset @offset  if @offset
+			@model
 		end
 
 		def fix_calculate
@@ -159,4 +216,75 @@ class SmqlToAR
 			@model
 		end
 	end
+
+	class SubBuilder < Array
+		attr_reader :parent, :_where
+		delegate :wobs, :joins, :includes, :sub_joins, :vid, :quote_column_name, :quote, :quote_table_name, :column, :to => :parent
+
+		def initialize parent, tmp = false
+			@parent = parent
+			@parent.where self  unless @parend.nil? && tmp
+		end
+
+		def new parent, tmp = false
+			super parent, tmp
+			#return parent  if self.class == parent.class
+			#super parent
+		end
+
+		alias where push
+
+		def type_correction!
+			collect! do |sub|
+				if sub.kind_of? Array
+					sub = default[ *sub]  unless sub.respond_to?( :type_correction!)
+					sub.type_correction!
+				end
+				sub
+			end
+			self
+		end
+
+		def optimize!
+			ext = []
+			collect! do |sub|
+				sub = sub.optimize!  if sub.kind_of? SubBuilder
+				if self.class == sub.class
+					ext.push *sub
+					nil
+				elsif sub.blank?
+					nil
+				elsif 1 == sub.size
+					sub.first
+				else
+					sub
+				end
+			end.compact!
+			push *ext
+			self
+		end
+
+		def inspect
+			"#{self.class.name.sub( /.*::/, '')}[ #{collect(&:inspect).join ', '}]"
+		end
+		def default()  SmqlToAR::And  end
+		def default_new( parent)  default.new self, parent, false  end
+		def collect_build_where indent = nil
+			indent = (indent||0) + 1
+			collect {|x| "(#{x.respond_to?( :build_where) ? x.build_where( indent) : x.to_s})" }
+		end
+	end
+
+	class And < SubBuilder
+		def default; SmqlToAR::Or; end
+		def build_where indent = nil
+			collect_build_where( indent).join " AND\n"+"\t"*(indent||0)
+		end
+	end
+
+	class Or < SubBuilder
+		def build_where indent = nil
+			collect_build_where( indent).join " OR\n"+"\t"*(indent||0)
+		end
+	end
 end