Squashed commit of the following:

commit 3c6727732b349551df342b9eee66ed53d47e53eb
Author: Aaron Patterson <aaron.patterson@gmail.com>
Date:   Mon Aug 23 14:11:34 2010 -0700

    adding table alias

4 files changed, 7 insertions, 2 deletions

diff --git a/lib/arel.rb b/lib/arel.rb
index 0d03d0a4bb..b012c62179 100644
--- a/lib/arel.rb
+++ b/lib/arel.rb
@@ -18,6 +18,7 @@ require 'arel/delete_manager'
 require 'arel/nodes'
 
 #### these are deprecated
+require 'arel/deprecated'
 require 'arel/sql/engine'
 require 'arel/sql_literal'
 require 'arel/expression'
diff --git a/lib/arel/deprecated.rb b/lib/arel/deprecated.rb
new file mode 100644
index 0000000000..28f96a8a8c
--- /dev/null
+++ b/lib/arel/deprecated.rb
@@ -0,0 +1,3 @@
+module Arel
+  InnerJoin = Nodes::InnerJoin
+end
diff --git a/lib/arel/table.rb b/lib/arel/table.rb
index 5a66db0627..02ece7ff07 100644
--- a/lib/arel/table.rb
+++ b/lib/arel/table.rb
@@ -5,7 +5,7 @@ module Arel
     @engine = nil
     class << self; attr_accessor :engine; end
 
-    attr_reader :name, :engine, :aliases
+    attr_reader :name, :engine, :aliases, :table_alias
 
     def initialize name, engine = Table.engine
       @name    = name
@@ -13,6 +13,7 @@ module Arel
       @engine  = engine[:engine] if Hash === engine
       @columns = nil
       @aliases = []
+      @table_alias = nil
     end
 
     def alias
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index 05c33ddb8b..6576d82c41 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -71,7 +71,7 @@ module Arel
       end
 
       def visit_Arel_Nodes_InnerJoin o
-        "#{visit o.left} INNER JOIN #{visit o.right} #{visit o.constraint}"
+        "#{visit o.left} INNER JOIN #{visit o.right} #{visit o.constraint if o.constraint}"
       end
 
       def visit_Arel_Nodes_On o