diff --git a/app/controllers/gantts_controller.rb b/app/controllers/gantts_controller.rb
index bc2d635..7ccafd1 100644
--- a/app/controllers/gantts_controller.rb
+++ b/app/controllers/gantts_controller.rb
@@ -15,23 +15,7 @@ class GanttsController < ApplicationController
     @gantt = Redmine::Helpers::Gantt.new(params)
     retrieve_query
     @query.group_by = nil
-    if @query.valid?
-      events = []
-      # Issues that have start and due dates
-      events += @query.issues(:include => [:tracker, :assigned_to, :priority],
-                              :order => "start_date, due_date",
-                              :conditions => ["(((start_date>=? and start_date<=?) or (due_date>=? and due_date<=?) or (start_date<? and due_date>?)) and start_date is not null and due_date is not null)", @gantt.date_from, @gantt.date_to, @gantt.date_from, @gantt.date_to, @gantt.date_from, @gantt.date_to]
-                              )
-      # Issues that don't have a due date but that are assigned to a version with a date
-      events += @query.issues(:include => [:tracker, :assigned_to, :priority, :fixed_version],
-                              :order => "start_date, effective_date",
-                              :conditions => ["(((start_date>=? and start_date<=?) or (effective_date>=? and effective_date<=?) or (start_date<? and effective_date>?)) and start_date is not null and due_date is null and effective_date is not null)", @gantt.date_from, @gantt.date_to, @gantt.date_from, @gantt.date_to, @gantt.date_from, @gantt.date_to]
-                              )
-      # Versions
-      events += @query.versions(:conditions => ["effective_date BETWEEN ? AND ?", @gantt.date_from, @gantt.date_to])
-                                   
-      @gantt.events = events
-    end
+    @gantt.fill_events_with_query(@query) if @query.valid?
     
     basename = (@project ? "#{@project.identifier}-" : '') + 'gantt'
     
diff --git a/lib/redmine/helpers/gantt.rb b/lib/redmine/helpers/gantt.rb
index 330b58e..18d8881 100644
--- a/lib/redmine/helpers/gantt.rb
+++ b/lib/redmine/helpers/gantt.rb
@@ -51,7 +51,24 @@ module Redmine
         @date_from = Date.civil(@year_from, @month_from, 1)
         @date_to = (@date_from >> @months) - 1
       end
-      
+
+      def fill_events_with_query(query)
+        events = []
+        # Issues that have start and due dates
+        events += query.issues(:include => [:tracker, :assigned_to, :priority],
+                               :order => "#{Issue.quoted_table_name}.start_date, #{Issue.quoted_table_name}.due_date",
+                               :conditions => conditions_for_issues_with_dates)
+
+        # Issues that don't have a due date but that are assigned to a version with a date
+        events += query.issues(:include => [:tracker, :assigned_to, :priority, :fixed_version],
+                               :order => "#{Issue.quoted_table_name}.start_date, #{Version.quoted_table_name}.effective_date",
+                               :conditions => conditions_for_issues_with_milestone_dates)
+
+        # Versions
+        events += query.versions(:conditions => ["#{Version.quoted_table_name}.effective_date BETWEEN ? AND ?", date_from, date_to])
+
+        self.events = events
+      end
       
       def events=(e)
         @events = e
@@ -269,6 +286,59 @@ module Redmine
           x.start_date <=> y.start_date
         end
       end
+
+      def conditions_for_issues_with_dates
+        [<<SQL, date_from, date_to, date_from, date_to, date_from, date_to]
+          (
+            (
+                (#{Issue.quoted_table_name}.start_date >= ? AND
+                    #{Issue.quoted_table_name}.start_date <= ?)
+              OR
+                (#{Issue.quoted_table_name}.due_date >= ? AND
+                    #{Issue.quoted_table_name}.due_date <= ?)
+              OR
+                (#{Issue.quoted_table_name}.start_date < ? AND
+                    #{Issue.quoted_table_name}.due_date > ?)
+            )
+            AND
+              #{Issue.quoted_table_name}.start_date IS NOT NULL
+            AND
+              #{Issue.quoted_table_name}.due_date IS NOT NULL
+          )
+SQL
+      end
+
+      def conditions_for_issues_with_milestone_dates
+        [<<SQL, date_from, date_to, date_from, date_to, date_from, date_to]
+          (
+            (
+                (
+                    #{Issue.quoted_table_name}.start_date >= ?
+                  AND
+                    #{Issue.quoted_table_name}.start_date <= ?
+                )
+              OR
+                (
+                    #{Version.quoted_table_name}.effective_date >= ?
+                  AND
+                    #{Version.quoted_table_name}.effective_date <= ?
+                )
+              OR
+                (
+                    #{Issue.quoted_table_name}.start_date < ?
+                  AND
+                    #{Version.quoted_table_name}.effective_date > ?
+                )
+            )
+            AND
+              #{Issue.quoted_table_name}.start_date IS NOT NULL
+            AND
+              #{Issue.quoted_table_name}.due_date IS NULL
+            AND
+              #{Version.quoted_table_name}.effective_date IS NOT NULL
+          )
+SQL
+      end
     end
   end
 end
-- 
1.7.1