implement own compare method

lib/report/query_utils.rb

@@ -1,4 +1,6 @@
 module Report::QueryUtils
+  Infinity = 1.0/0
+
   alias singleton_class metaclass unless respond_to? :singleton_class
 
   delegate :quoted_false, :quoted_true, :to => "engine.reporting_connection"
@@ -217,6 +219,15 @@ module Report::QueryUtils
     Report::QueryUtils.cache
   end
 
+  def compare(first, second)
+    first  = Array(first).flatten
+    second = Array(second).flatten
+    first.zip second do |a, b|
+      return (a <=> b) || (a == Infinity ? 1 : -1) if a != b
+    end
+    second.size > first.size ? -1 : 0
+  end
+
   def mysql?
     [:mysql, :mysql2].include? adapter_name.to_s.downcase.to_sym
   end

lib/report/result.rb

@@ -106,7 +106,6 @@ class Report::Result
     def set_key(index = [])
       self.key = index.map { |k| map_field(k, fields[k]) }
     end
-
   end
 
   class DirectResult < Base
@@ -155,7 +154,7 @@ class Report::Result
 
     def sort!(force = false)
       return false if @sorted and not force
-      values.sort! { |a,b| a.key <=> b.key }
+      values.sort! { |a,b| compare a.key, b.key }
       values.each { |e| e.sort! force }
       @sorted = true
     end

lib/report/table.rb

@@ -78,7 +78,7 @@ class Report::Table
     @indexes ||= begin
       indexes = Hash.new { |h,k| h[k] = Set.new }
       query.each_direct_result { |result| [:row, :column].each { |t| indexes[t] << fields_from(result, t) } }
-      indexes.keys.each { |k| indexes[k] = indexes[k].sort { |x, y| x <=> y } }
+      indexes.keys.each { |k| indexes[k] = indexes[k].sort { |x, y| compare x, y } }
       indexes
     end
     @indexes[type]