Add Model.having and Relation#having

activerecord/CHANGELOG

 *Edge*
 
+* Add Model.having and Relation#having. [Pratik Naik]
+
+  Developer.group("salary").having("sum(salary) >  10000").select("salary")
+
 * Add Relation#count. [Pratik Naik]
 
   legends = People.where("age > 100")

activerecord/lib/active_record/associations.rb

@@ -1715,7 +1715,8 @@ def construct_finder_arel_with_included_associations(options, join_dependency)
 
           relation = relation.joins(construct_join(options[:joins], scope)).
             select(column_aliases(join_dependency)).
-            group(construct_group(options[:group], options[:having], scope)).
+            group(options[:group] || (scope && scope[:group])).
+            having(options[:having] || (scope && scope[:having])).
             order(construct_order(options[:order], scope)).
             where(construct_conditions(options[:conditions], scope)).
             from((scope && scope[:from]) || options[:from])
@@ -1759,7 +1760,8 @@ def construct_finder_sql_for_association_limiting(options, join_dependency)
 
           relation = relation.joins(construct_join(options[:joins], scope)).
             where(construct_conditions(options[:conditions], scope)).
-            group(construct_group(options[:group], options[:having], scope)).
+            group(options[:group] || (scope && scope[:group])).
+            having(options[:having] || (scope && scope[:having])).
             order(construct_order(options[:order], scope)).
             limit(construct_limit(options[:limit], scope)).
             offset(construct_limit(options[:offset], scope)).

activerecord/lib/active_record/associations/association_collection.rb

@@ -21,7 +21,7 @@ def initialize(owner, reflection)
         construct_sql
       end
 
-      delegate :group, :order, :limit, :joins, :where, :preload, :eager_load, :from, :lock, :readonly, :to => :scoped
+      delegate :group, :order, :limit, :joins, :where, :preload, :eager_load, :from, :lock, :readonly, :having, :to => :scoped
 
       def select(select = nil, &block)
         if block_given?

activerecord/lib/active_record/base.rb

@@ -652,7 +652,7 @@ def find(*args)
         end
       end
 
-      delegate :select, :group, :order, :limit, :joins, :where, :preload, :eager_load, :from, :lock, :readonly, :to => :scoped
+      delegate :select, :group, :order, :limit, :joins, :where, :preload, :eager_load, :from, :lock, :readonly, :having, :to => :scoped
 
       # A convenience wrapper for <tt>find(:first, *args)</tt>. You can pass in all the
       # same arguments to this method as you can to <tt>find(:first)</tt>.
@@ -1566,7 +1566,8 @@ def construct_finder_arel(options = {}, scope = scope(:find))
             joins(construct_join(options[:joins], scope)).
             where(construct_conditions(options[:conditions], scope)).
             select(options[:select] || (scope && scope[:select]) || default_select(options[:joins] || (scope && scope[:joins]))).
-            group(construct_group(options[:group], options[:having], scope)).
+            group(options[:group] || (scope && scope[:group])).
+            having(options[:having] || (scope && scope[:having])).
             order(construct_order(options[:order], scope)).
             limit(construct_limit(options[:limit], scope)).
             offset(construct_offset(options[:offset], scope)).
@@ -1611,18 +1612,6 @@ def construct_join(joins, scope)
           end
         end
 
-        def construct_group(group, having, scope)
-          sql = ''
-          if group
-            sql << group.to_s
-            sql << " HAVING #{sanitize_sql_for_conditions(having)}" if having
-          elsif scope && (scoped_group = scope[:group])
-            sql << scoped_group.to_s
-            sql << " HAVING #{sanitize_sql_for_conditions(scope[:having])}" if scope[:having]
-          end
-          sql
-        end
-
         def construct_order(order, scope)
           orders = []
 

activerecord/lib/active_record/calculations.rb

@@ -194,7 +194,7 @@ def execute_grouped_calculation(operation, column_name, options, relation) #:nod
 
         options[:select] <<  ", #{group_field} AS #{group_alias}"
 
-        relation = relation.select(options[:select]).group(construct_group(options[:group], options[:having], nil))
+        relation = relation.select(options[:select]).group(options[:group]).having(options[:having])
 
         calculated_data = connection.select_all(relation.to_sql)
 

activerecord/lib/active_record/relation.rb

@@ -55,6 +55,18 @@ def from(from)
       from.present? ? create_new_relation(@relation.from(from)) : create_new_relation
     end
 
+    def having(*args)
+      return create_new_relation if args.blank?
+
+      if [String, Hash, Array].include?(args.first.class)
+        havings = @klass.send(:merge_conditions, args.size > 1 ? Array.wrap(args) : args.first)
+      else
+        havings = args.first
+      end
+
+      create_new_relation(@relation.having(havings))
+    end
+
     def group(groups)
       groups.present? ? create_new_relation(@relation.group(groups)) : create_new_relation
     end