diff --git a/lib/rasti/db/nql/nodes/comparisons/base.rb b/lib/rasti/db/nql/nodes/comparisons/base.rb
index 370f740..7114bae 100644
--- a/lib/rasti/db/nql/nodes/comparisons/base.rb
+++ b/lib/rasti/db/nql/nodes/comparisons/base.rb
@@ -6,7 +6,7 @@ module Comparisons
           class Base < Treetop::Runtime::SyntaxNode
 
             def dependency_tables
-              left.tables.empty? ? [] : [left.tables.join('.')]
+              field.tables.empty? ? [] : [field.tables.join('.')]
             end
 
           end
diff --git a/lib/rasti/db/nql/nodes/comparisons/equal.rb b/lib/rasti/db/nql/nodes/comparisons/equal.rb
index 0feeba4..83c3819 100644
--- a/lib/rasti/db/nql/nodes/comparisons/equal.rb
+++ b/lib/rasti/db/nql/nodes/comparisons/equal.rb
@@ -6,7 +6,7 @@ module Comparisons
           class Equal < Base
 
             def to_filter
-              { left.to_filter => right.value }
+              { field.identifier => argument.value }
             end
 
           end
diff --git a/lib/rasti/db/nql/nodes/comparisons/greater_than.rb b/lib/rasti/db/nql/nodes/comparisons/greater_than.rb
index 324bc17..e8e915c 100644
--- a/lib/rasti/db/nql/nodes/comparisons/greater_than.rb
+++ b/lib/rasti/db/nql/nodes/comparisons/greater_than.rb
@@ -6,7 +6,7 @@ module Comparisons
           class GreaterThan < Base
 
             def to_filter
-              left.to_filter > right.value
+              field.identifier > argument.value
             end
 
           end
diff --git a/lib/rasti/db/nql/nodes/comparisons/greater_than_or_equal.rb b/lib/rasti/db/nql/nodes/comparisons/greater_than_or_equal.rb
index daea6e8..f512811 100644
--- a/lib/rasti/db/nql/nodes/comparisons/greater_than_or_equal.rb
+++ b/lib/rasti/db/nql/nodes/comparisons/greater_than_or_equal.rb
@@ -6,7 +6,7 @@ module Comparisons
           class GreaterThanOrEqual < Base
 
             def to_filter
-              left.to_filter >= right.value
+              field.identifier >= argument.value
             end
 
           end
diff --git a/lib/rasti/db/nql/nodes/comparisons/include.rb b/lib/rasti/db/nql/nodes/comparisons/include.rb
index b60bc14..f9ec51b 100644
--- a/lib/rasti/db/nql/nodes/comparisons/include.rb
+++ b/lib/rasti/db/nql/nodes/comparisons/include.rb
@@ -6,7 +6,7 @@ module Comparisons
           class Include < Base
 
             def to_filter
-              Sequel.ilike(left.to_filter, "%#{right.value}%")
+              Sequel.ilike(field.identifier, "%#{argument.value}%")
             end
 
           end
diff --git a/lib/rasti/db/nql/nodes/comparisons/less_than.rb b/lib/rasti/db/nql/nodes/comparisons/less_than.rb
index c0a6ead..243508b 100644
--- a/lib/rasti/db/nql/nodes/comparisons/less_than.rb
+++ b/lib/rasti/db/nql/nodes/comparisons/less_than.rb
@@ -6,7 +6,7 @@ module Comparisons
           class LessThan < Base
 
             def to_filter
-              left.to_filter < right.value
+              field.identifier < argument.value
             end
 
           end
diff --git a/lib/rasti/db/nql/nodes/comparisons/less_than_or_equal.rb b/lib/rasti/db/nql/nodes/comparisons/less_than_or_equal.rb
index 59c1089..ae85f46 100644
--- a/lib/rasti/db/nql/nodes/comparisons/less_than_or_equal.rb
+++ b/lib/rasti/db/nql/nodes/comparisons/less_than_or_equal.rb
@@ -6,7 +6,7 @@ module Comparisons
           class LessThanOrEqual < Base
 
             def to_filter
-              left.to_filter <= right.value
+              field.identifier <= argument.value
             end
             
           end
diff --git a/lib/rasti/db/nql/nodes/comparisons/like.rb b/lib/rasti/db/nql/nodes/comparisons/like.rb
index cc0797e..c43bf37 100644
--- a/lib/rasti/db/nql/nodes/comparisons/like.rb
+++ b/lib/rasti/db/nql/nodes/comparisons/like.rb
@@ -6,7 +6,7 @@ module Comparisons
           class Like < Base
 
             def to_filter
-              Sequel.ilike(left.to_filter, right.value)
+              Sequel.ilike(field.identifier, argument.value)
             end
 
           end
diff --git a/lib/rasti/db/nql/nodes/comparisons/not_equal.rb b/lib/rasti/db/nql/nodes/comparisons/not_equal.rb
index 3128129..1953a0d 100644
--- a/lib/rasti/db/nql/nodes/comparisons/not_equal.rb
+++ b/lib/rasti/db/nql/nodes/comparisons/not_equal.rb
@@ -6,7 +6,7 @@ module Comparisons
           class NotEqual < Base
 
             def to_filter
-              Sequel.negate(left.to_filter => right.value)
+              Sequel.negate(field.identifier => argument.value)
             end
 
           end
diff --git a/lib/rasti/db/nql/nodes/comparisons/not_include.rb b/lib/rasti/db/nql/nodes/comparisons/not_include.rb
index 2898569..c884b95 100644
--- a/lib/rasti/db/nql/nodes/comparisons/not_include.rb
+++ b/lib/rasti/db/nql/nodes/comparisons/not_include.rb
@@ -6,7 +6,7 @@ module Comparisons
           class NotInclude < Base
 
             def to_filter
-              ~ Sequel.ilike(left.to_filter, "%#{right.value}%")
+              ~ Sequel.ilike(field.identifier, "%#{argument.value}%")
             end
 
           end
diff --git a/lib/rasti/db/nql/nodes/field.rb b/lib/rasti/db/nql/nodes/field.rb
index a517e38..ff722dc 100644
--- a/lib/rasti/db/nql/nodes/field.rb
+++ b/lib/rasti/db/nql/nodes/field.rb
@@ -4,7 +4,7 @@ module NQL
       module Nodes
         class Field < Treetop::Runtime::SyntaxNode
 
-          def to_filter
+          def identifier
             tables.empty? ? Sequel[column.to_sym] : Sequel[tables.join('__').to_sym][column.to_sym]
           end
 
diff --git a/lib/rasti/db/nql/syntax.rb b/lib/rasti/db/nql/syntax.rb
index da2459a..3912b2f 100644
--- a/lib/rasti/db/nql/syntax.rb
+++ b/lib/rasti/db/nql/syntax.rb
@@ -510,7 +510,7 @@ def _nt_field
         end
 
         module ComparisonInclude0
-          def left
+          def field
             elements[0]
           end
 
@@ -518,7 +518,7 @@ def comparator
             elements[2]
           end
 
-          def right
+          def argument
             elements[4]
           end
         end
@@ -591,7 +591,7 @@ def _nt_comparison_include
         end
 
         module ComparisonNotInclude0
-          def left
+          def field
             elements[0]
           end
 
@@ -599,7 +599,7 @@ def comparator
             elements[2]
           end
 
-          def right
+          def argument
             elements[4]
           end
         end
@@ -672,7 +672,7 @@ def _nt_comparison_not_include
         end
 
         module ComparisonLike0
-          def left
+          def field
             elements[0]
           end
 
@@ -680,7 +680,7 @@ def comparator
             elements[2]
           end
 
-          def right
+          def argument
             elements[4]
           end
         end
@@ -753,7 +753,7 @@ def _nt_comparison_like
         end
 
         module ComparisonGreaterThan0
-          def left
+          def field
             elements[0]
           end
 
@@ -761,7 +761,7 @@ def comparator
             elements[2]
           end
 
-          def right
+          def argument
             elements[4]
           end
         end
@@ -834,7 +834,7 @@ def _nt_comparison_greater_than
         end
 
         module ComparisonGreaterThanOrEqual0
-          def left
+          def field
             elements[0]
           end
 
@@ -842,7 +842,7 @@ def comparator
             elements[2]
           end
 
-          def right
+          def argument
             elements[4]
           end
         end
@@ -915,7 +915,7 @@ def _nt_comparison_greater_than_or_equal
         end
 
         module ComparisonLessThan0
-          def left
+          def field
             elements[0]
           end
 
@@ -923,7 +923,7 @@ def comparator
             elements[2]
           end
 
-          def right
+          def argument
             elements[4]
           end
         end
@@ -996,7 +996,7 @@ def _nt_comparison_less_than
         end
 
         module ComparisonLessThanOrEqual0
-          def left
+          def field
             elements[0]
           end
 
@@ -1004,7 +1004,7 @@ def comparator
             elements[2]
           end
 
-          def right
+          def argument
             elements[4]
           end
         end
@@ -1077,7 +1077,7 @@ def _nt_comparison_less_than_or_equal
         end
 
         module ComparisonNotEqual0
-          def left
+          def field
             elements[0]
           end
 
@@ -1085,7 +1085,7 @@ def comparator
             elements[2]
           end
 
-          def right
+          def argument
             elements[4]
           end
         end
@@ -1158,7 +1158,7 @@ def _nt_comparison_not_equal
         end
 
         module ComparisonEqual0
-          def left
+          def field
             elements[0]
           end
 
@@ -1166,7 +1166,7 @@ def comparator
             elements[2]
           end
 
-          def right
+          def argument
             elements[4]
           end
         end
diff --git a/lib/rasti/db/nql/syntax.treetop b/lib/rasti/db/nql/syntax.treetop
index ddcd6ac..025ecfd 100644
--- a/lib/rasti/db/nql/syntax.treetop
+++ b/lib/rasti/db/nql/syntax.treetop
@@ -47,39 +47,39 @@ module Rasti
         end
 
         rule comparison_include
-          left:field space* comparator:':' space* right:basic <Nodes::Comparisons::Include>
+          field:field space* comparator:':' space* argument:basic <Nodes::Comparisons::Include>
         end
 
         rule comparison_not_include
-          left:field space* comparator:'!:' space* right:basic <Nodes::Comparisons::NotInclude>
+          field:field space* comparator:'!:' space* argument:basic <Nodes::Comparisons::NotInclude>
         end
 
         rule comparison_like
-          left:field space* comparator:'~' space* right:basic <Nodes::Comparisons::Like>
+          field:field space* comparator:'~' space* argument:basic <Nodes::Comparisons::Like>
         end
 
         rule comparison_greater_than
-          left:field space* comparator:'>' space* right:basic <Nodes::Comparisons::GreaterThan>
+          field:field space* comparator:'>' space* argument:basic <Nodes::Comparisons::GreaterThan>
         end
 
         rule comparison_greater_than_or_equal
-          left:field space* comparator:'>=' space* right:basic <Nodes::Comparisons::GreaterThanOrEqual>
+          field:field space* comparator:'>=' space* argument:basic <Nodes::Comparisons::GreaterThanOrEqual>
         end
 
         rule comparison_less_than
-          left:field space* comparator:'<' space* right:basic <Nodes::Comparisons::LessThan>
+          field:field space* comparator:'<' space* argument:basic <Nodes::Comparisons::LessThan>
         end
 
         rule comparison_less_than_or_equal
-          left:field space* comparator:'<=' space* right:basic <Nodes::Comparisons::LessThanOrEqual>
+          field:field space* comparator:'<=' space* argument:basic <Nodes::Comparisons::LessThanOrEqual>
         end
 
         rule comparison_not_equal
-          left:field space* comparator:'!=' space* right:basic <Nodes::Comparisons::NotEqual>
+          field:field space* comparator:'!=' space* argument:basic <Nodes::Comparisons::NotEqual>
         end
 
         rule comparison_equal
-          left:field space* comparator:'=' space* right:basic <Nodes::Comparisons::Equal>
+          field:field space* comparator:'=' space* argument:basic <Nodes::Comparisons::Equal>
         end
 
         rule basic
diff --git a/spec/nql/syntax_parser_spec.rb b/spec/nql/syntax_parser_spec.rb
index 0424cd5..adb3c4d 100644
--- a/spec/nql/syntax_parser_spec.rb
+++ b/spec/nql/syntax_parser_spec.rb
@@ -31,8 +31,8 @@ def parse(expression)
           proposition = tree.proposition
           proposition.must_be_instance_of node_class
           proposition.comparator.text_value.must_equal comparator
-          proposition.left.text_value.must_equal 'column'
-          proposition.right.text_value.must_equal 'value'
+          proposition.field.text_value.must_equal 'column'
+          proposition.argument.text_value.must_equal 'value'
         end
       end
 
@@ -44,8 +44,8 @@ def parse(expression)
       proposition = tree.proposition
       proposition.must_be_instance_of Rasti::DB::NQL::Nodes::Comparisons::Equal
       proposition.comparator.text_value.must_equal '='
-      proposition.left.text_value.must_equal 'column'
-      proposition.right.text_value.must_equal 'value'
+      proposition.field.text_value.must_equal 'column'
+      proposition.argument.text_value.must_equal 'value'
     end
 
     describe 'Right hand Operand' do
@@ -53,7 +53,7 @@ def parse(expression)
       it 'must parse expression with integer' do
         tree = parse 'column = 1'
 
-        right_hand_operand = tree.proposition.right
+        right_hand_operand = tree.proposition.argument
         right_hand_operand.must_be_instance_of Rasti::DB::NQL::Nodes::Constants::Integer
         right_hand_operand.value.must_equal 1
       end
@@ -61,7 +61,7 @@ def parse(expression)
       it 'must parse expression with float' do
         tree = parse 'column = 2.3'
 
-        right_hand_operand = tree.proposition.right
+        right_hand_operand = tree.proposition.argument
         right_hand_operand.must_be_instance_of Rasti::DB::NQL::Nodes::Constants::Float
         right_hand_operand.value.must_equal 2.3
       end
@@ -69,7 +69,7 @@ def parse(expression)
       it 'must parse expression with true' do
         tree = parse 'column = true'
 
-        right_hand_operand = tree.proposition.right
+        right_hand_operand = tree.proposition.argument
         right_hand_operand.must_be_instance_of Rasti::DB::NQL::Nodes::Constants::True
         right_hand_operand.value.must_equal true
       end
@@ -77,7 +77,7 @@ def parse(expression)
       it 'must parse expression with false' do
         tree = parse 'column = false'
 
-        right_hand_operand = tree.proposition.right
+        right_hand_operand = tree.proposition.argument
         right_hand_operand.must_be_instance_of Rasti::DB::NQL::Nodes::Constants::False
         right_hand_operand.value.must_equal false
       end
@@ -85,7 +85,7 @@ def parse(expression)
       it 'must parse expression with string' do
         tree = parse 'column = String1 '
 
-        right_hand_operand = tree.proposition.right
+        right_hand_operand = tree.proposition.argument
         right_hand_operand.must_be_instance_of Rasti::DB::NQL::Nodes::Constants::String
         right_hand_operand.value.must_equal 'String1'
       end
@@ -93,7 +93,7 @@ def parse(expression)
       it 'must parse expression with literal string' do
         tree = parse 'column = "a & (b | c) | d:=e"'
 
-        right_hand_operand = tree.proposition.right
+        right_hand_operand = tree.proposition.argument
         right_hand_operand.must_be_instance_of Rasti::DB::NQL::Nodes::Constants::LiteralString
         right_hand_operand.value.must_equal 'a & (b | c) | d:=e'
       end
@@ -103,7 +103,7 @@ def parse(expression)
         it 'must parse expression with hours and minutes' do
           tree = parse 'column > 12:20'
 
-          right_hand_operand = tree.proposition.right
+          right_hand_operand = tree.proposition.argument
           right_hand_operand.must_be_instance_of Rasti::DB::NQL::Nodes::Constants::Time
           right_hand_operand.value.must_equal Timing::TimeInZone.parse('12:20').to_s
         end
@@ -111,7 +111,7 @@ def parse(expression)
         it 'must parse expression with date, hours, minutes and seconds' do
           tree = parse 'column > 2019-03-27T12:20:00'
 
-          right_hand_operand = tree.proposition.right
+          right_hand_operand = tree.proposition.argument
           right_hand_operand.must_be_instance_of Rasti::DB::NQL::Nodes::Constants::Time
           right_hand_operand.value.must_equal Timing::TimeInZone.parse('2019-03-27T12:20:00').to_s
         end
@@ -119,7 +119,7 @@ def parse(expression)
         it 'must parse expression with date, hours, minutes, seconds and timezone' do
           tree = parse 'column > 2019-03-27T12:20:00-03:00'
 
-          right_hand_operand = tree.proposition.right
+          right_hand_operand = tree.proposition.argument
           right_hand_operand.must_be_instance_of Rasti::DB::NQL::Nodes::Constants::Time
           right_hand_operand.value.must_equal Timing::TimeInZone.parse('2019-03-27T12:20:00-03:00').to_s
         end
@@ -131,7 +131,7 @@ def parse(expression)
     it 'must parse expression with field with tables' do
       tree = parse 'relation_table_one.relation_table_two.column = 1'
 
-      left_hand_operand = tree.proposition.left
+      left_hand_operand = tree.proposition.field
       left_hand_operand.tables.must_equal ['relation_table_one', 'relation_table_two']
       left_hand_operand.column.must_equal 'column'
     end