inserting false works a bit better

lib/arel/visitors/to_sql.rb

@@ -43,7 +43,7 @@ def visit_Arel_Nodes_InsertStatement o
 
       def visit_Arel_Nodes_Values o
         "VALUES (#{o.expressions.map { |value|
-          value ? visit(value) : 'NULL'
+          value.nil? ? 'NULL' : visit(value)
         }.join ', '})"
       end
 

spec/arel/insert_manager_spec.rb

@@ -9,6 +9,15 @@ module Arel
     end
 
     describe 'insert' do
+      it "inserts false" do
+        table = Table.new(:users)
+        manager = Arel::InsertManager.new Table.engine
+        manager.insert [[table[:id], false]]
+        manager.to_sql.should be_like %{
+          INSERT INTO "users" ("id") VALUES ('f')
+        }
+      end
+
       it "inserts null" do
         table = Table.new(:users)
         manager = Arel::InsertManager.new Table.engine