diff --git a/lib/lotus/model/adapters/memory/query.rb b/lib/lotus/model/adapters/memory/query.rb
index 24994c1e..196944c7 100644
--- a/lib/lotus/model/adapters/memory/query.rb
+++ b/lib/lotus/model/adapters/memory/query.rb
@@ -22,6 +22,14 @@ def where(condition)
           alias_method :and, :where
           alias_method :or,  :where
 
+          def exclude(condition)
+            column, value = *Array(condition).flatten
+            conditions.push(Proc.new{ reject! {|r| r.fetch(column) == value} })
+            self
+          end
+
+          alias_method :not, :exclude
+
           def order(column)
             conditions.push(Proc.new{ sort_by{|r| r.fetch(column)} })
             self
@@ -90,14 +98,11 @@ def range(column)
 
           private
           def run
-            # TODO cleanup
-            result = if conditions.any?
-                       conditions.map do |condition|
-                         @collection.all.instance_exec(&condition)
-                       end
-                     else
-                       @collection.all
-                     end
+            result = @collection.all.dup
+
+            result = conditions.map do |condition|
+              result.instance_exec(&condition)
+            end if conditions.any?
 
             modifiers.map do |modifier|
               result.instance_exec(&modifier)
diff --git a/lib/lotus/model/adapters/sql/query.rb b/lib/lotus/model/adapters/sql/query.rb
index fdf81f97..f2076dad 100644
--- a/lib/lotus/model/adapters/sql/query.rb
+++ b/lib/lotus/model/adapters/sql/query.rb
@@ -25,6 +25,13 @@ def where(condition)
 
           alias_method :and, :where
 
+          def exclude(condition)
+            conditions.push([:exclude, condition])
+            self
+          end
+
+          alias_method :not, :exclude
+
           def limit(number)
             conditions.push([:limit, number])
             self
diff --git a/test/model/adapters/memory_adapter_test.rb b/test/model/adapters/memory_adapter_test.rb
index 5211b885..37819ca7 100644
--- a/test/model/adapters/memory_adapter_test.rb
+++ b/test/model/adapters/memory_adapter_test.rb
@@ -303,6 +303,64 @@
       end
     end
 
+    describe 'exclude' do
+      describe 'with an empty collection' do
+        it 'returns an empty result set' do
+          result = @adapter.query(collection) do
+            exclude(id: 23)
+          end.all
+
+          result.must_be_empty
+        end
+      end
+
+      describe 'with a filled collection' do
+        before do
+          @adapter.create(collection, user1)
+          @adapter.create(collection, user2)
+          @adapter.create(collection, user3)
+        end
+
+        let(:user3) { TestUser.new(name: 'S', age: 2) }
+
+        it 'returns selected records' do
+          id = user1.id
+
+          query = Proc.new {
+            exclude(id: id)
+          }
+
+          result = @adapter.query(collection, &query).all
+          result.must_equal [user2, user3]
+        end
+
+        it 'can use multiple exclude conditions' do
+          id   = user1.id
+          name = user2.name
+
+          query = Proc.new {
+            exclude(id: id).exclude(name: name)
+          }
+
+          $debug = true
+          result = @adapter.query(collection, &query).all
+          result.must_equal [user3]
+        end
+
+        it 'can use multiple exclude conditions with "not" alias' do
+          id   = user1.id
+          name = user2.name
+
+          query = Proc.new {
+            self.not(id: id).not(name: name)
+          }
+
+          result = @adapter.query(collection, &query).all
+          result.must_equal [user3]
+        end
+      end
+    end
+
     describe 'or' do
       describe 'with an empty collection' do
         it 'returns an empty result set' do
diff --git a/test/model/adapters/sql_adapter_test.rb b/test/model/adapters/sql_adapter_test.rb
index fcb8b7a1..5f51792c 100644
--- a/test/model/adapters/sql_adapter_test.rb
+++ b/test/model/adapters/sql_adapter_test.rb
@@ -294,6 +294,63 @@
       end
     end
 
+    describe 'exclude' do
+      describe 'with an empty collection' do
+        it 'returns an empty result set' do
+          result = @adapter.query(collection) do
+            exclude(id: 23)
+          end.all
+
+          result.must_be_empty
+        end
+      end
+
+      describe 'with a filled collection' do
+        before do
+          @adapter.create(collection, user1)
+          @adapter.create(collection, user2)
+          @adapter.create(collection, user3)
+        end
+
+        let(:user3) { TestUser.new(name: 'S', age: 2) }
+
+        it 'returns selected records' do
+          id = user1.id
+
+          query = Proc.new {
+            exclude(id: id)
+          }
+
+          result = @adapter.query(collection, &query).all
+          result.must_equal [user2, user3]
+        end
+
+        it 'can use multiple exclude conditions' do
+          id   = user1.id
+          name = user2.name
+
+          query = Proc.new {
+            exclude(id: id).exclude(name: name)
+          }
+
+          result = @adapter.query(collection, &query).all
+          result.must_equal [user3]
+        end
+
+        it 'can use multiple exclude conditions with "not" alias' do
+          id   = user1.id
+          name = user2.name
+
+          query = Proc.new {
+            self.not(id: id).not(name: name)
+          }
+
+          result = @adapter.query(collection, &query).all
+          result.must_equal [user3]
+        end
+      end
+    end
+
     describe 'or' do
       describe 'with an empty collection' do
         it 'returns an empty result set' do