diff --git a/lib/report/result.rb b/lib/report/result.rb
index 5b34fc3a48..97ee2773a1 100644
--- a/lib/report/result.rb
+++ b/lib/report/result.rb
@@ -31,6 +31,24 @@ class Report::Result
       fields[key]
     end
 
+    ##
+    # Override if you want to influence the result grouping.
+    #
+    # @return A value for grouping or nil if the given field should
+    #         not be considered for grouping.
+    def map_group_by_value(key, value)
+      value
+    end
+
+    ##
+    # This method is called when this result is requested as #grouped_by something
+    # just before the result is returned.
+    #
+    # @param data This result's grouped data.
+    def group_by_data_ready(data)
+      # good to know!
+    end
+
     def grouped_by(fields, type, important_fields = [])
       @grouped_by ||= {}
       list = begin
@@ -40,8 +58,12 @@ class Report::Result
           data = group_by do |entry|
             # index for group is a hash
             # i.e. { :foo => 10, :bar => 20 } <= this is just the KEY!!!!
-            fields.inject({}) { |hash, key| hash.merge key => entry.fields[key] }
+            fields.inject({}) do |hash, key|
+              val = map_group_by_value(key, entry.fields[key])
+              hash.merge key => val
+            end
           end
+          group_by_data_ready(data)
           # map group back to array, all fields with same key get grouped into one list
           data.keys.map { |f| engine::Result.new data[f], f, type, important_fields }
         end
diff --git a/lib/report/sql_statement.rb b/lib/report/sql_statement.rb
index 5062937c35..07e98d3b11 100644
--- a/lib/report/sql_statement.rb
+++ b/lib/report/sql_statement.rb
@@ -175,7 +175,7 @@ class Report::SqlStatement
     return(@select || default_select) if fields.empty?
     (@select ||= []).tap do
       @sql = nil
-      fields.each do |f|
+      fields.reject {|f| never_select.include? f}.each do |f|
         case f
         when Array
           if f.size == 2 and f.first.respond_to? :table_name then select field_name_for(f)
@@ -193,6 +193,22 @@ class Report::SqlStatement
     end
   end
 
+  def unselect(*fields)
+    @sql = nil
+    @select = @select.reject do |field|
+      fields.find { |f| f == field }
+    end
+  end
+
+  def never_select(*fields)
+    (@never_select ||= []).tap do
+      unless fields.empty?
+        @never_select += fields
+        unselect *fields
+      end
+    end
+  end
+
   ##
   # Return the names which have been bound through select statements
   # @return [Array<String>] All fields for select part
@@ -210,7 +226,7 @@ class Report::SqlStatement
   def group_by(*fields)
     @sql = nil unless fields.empty?
     (@group_by ||= []).tap do
-      fields.each do |e|
+      fields.reject {|f| never_group_by.include? f}.each do |e|
         if e.is_a? Array and (e.size != 2 or !e.first.respond_to? :table_name)
           group_by(*e)
         else
@@ -221,6 +237,22 @@ class Report::SqlStatement
     end
   end
 
+  def group_not_by(*fields)
+    @sql = nil
+    @group_by = @group_by.reject do |field|
+      fields.find { |f| f == field }
+    end
+  end
+
+  def never_group_by(*fields)
+    (@never_group_by ||= []).tap do
+      unless fields.empty?
+        @never_group_by += fields
+        group_not_by *fields
+      end
+    end
+  end
+
   ##
   # @return [TrueClass, FalseClass] Whether or not to add a group by part.
   def group_by?