1 files changed, 33 insertions, 0 deletions
diff --git a/lib/arel/engines/sql/relations/operations/join.rb b/lib/arel/engines/sql/relations/operations/join.rb
new file mode 100644
index 0000000000..7c5e13510a
--- /dev/null
+++ b/lib/arel/engines/sql/relations/operations/join.rb
@@ -0,0 +1,33 @@
+module Arel
+  class Join < Relation
+    def table_sql(formatter = Sql::TableReference.new(self))
+      relation1.externalize.table_sql(formatter)
+    end
+
+    def joins(environment, formatter = Sql::TableReference.new(environment))
+      @joins ||= begin
+        this_join = [
+          join_sql,
+          relation2.externalize.table_sql(formatter),
+          ("ON" unless predicates.blank?),
+          (ons + relation2.externalize.wheres).collect { |p| p.bind(environment).to_sql(Sql::WhereClause.new(environment)) }.join(' AND ')
+        ].compact.join(" ")
+        [relation1.joins(environment), this_join, relation2.joins(environment)].compact.join(" ")
+      end
+    end
+  end
+
+  class InnerJoin < Join
+    def join_sql; "INNER JOIN" end
+  end
+
+  class OuterJoin < Join
+    def join_sql; "LEFT OUTER JOIN" end
+  end
+
+  class StringJoin < Join
+    def joins(_, __ = nil)
+      relation2
+    end
+  end
+end