Add :having option to find, to use in combination with grouped finds. Also added to has_many and has_and_belongs_to_many associations.

Signed-off-by: Michael Koziarski <michael@koziarski.com>
[#1028 state:committed]

3 files changed, 15 insertions, 7 deletions

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 0546b76c63..3fbbea43ed 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -724,6 +724,8 @@ module ActiveRecord
       #   Specify second-order associations that should be eager loaded when the collection is loaded.
       # [:group]
       #   An attribute name by which the result should be grouped. Uses the <tt>GROUP BY</tt> SQL-clause.
+      # [:having]
+      #   Combined with +:group+ this can be used to filter the records that a <tt>GROUP BY</tt> returns. Uses the <tt>HAVING</tt> SQL-clause.
       # [:limit]
       #   An integer determining the limit on the number of rows that should be returned.
       # [:offset]
@@ -1181,6 +1183,8 @@ module ActiveRecord
       #   Specify second-order associations that should be eager loaded when the collection is loaded.
       # [:group]
       #   An attribute name by which the result should be grouped. Uses the <tt>GROUP BY</tt> SQL-clause.
+      # [:having]
+      #   Combined with +:group+ this can be used to filter the records that a <tt>GROUP BY</tt> returns. Uses the <tt>HAVING</tt> SQL-clause.
       # [:limit]
       #   An integer determining the limit on the number of rows that should be returned.
       # [:offset]
@@ -1553,7 +1557,7 @@ module ActiveRecord
         @@valid_keys_for_has_many_association = [
           :class_name, :table_name, :foreign_key, :primary_key,
           :dependent,
-          :select, :conditions, :include, :order, :group, :limit, :offset,
+          :select, :conditions, :include, :order, :group, :having, :limit, :offset,
           :as, :through, :source, :source_type,
           :uniq,
           :finder_sql, :counter_sql,
@@ -1609,7 +1613,7 @@ module ActiveRecord
         mattr_accessor :valid_keys_for_has_and_belongs_to_many_association
         @@valid_keys_for_has_and_belongs_to_many_association = [
           :class_name, :table_name, :join_table, :foreign_key, :association_foreign_key,
-          :select, :conditions, :include, :order, :group, :limit, :offset,
+          :select, :conditions, :include, :order, :group, :having, :limit, :offset,
           :uniq,
           :finder_sql, :counter_sql, :delete_sql, :insert_sql,
           :before_add, :after_add, :before_remove, :after_remove,
@@ -1658,7 +1662,7 @@ module ActiveRecord
           add_conditions!(sql, options[:conditions], scope)
           add_limited_ids_condition!(sql, options, join_dependency) if !using_limitable_reflections?(join_dependency.reflections) && ((scope && scope[:limit]) || options[:limit])
 
-          add_group!(sql, options[:group], scope)
+          add_group!(sql, options[:group], options[:having], scope)
           add_order!(sql, options[:order], scope)
           add_limit!(sql, options, scope) if using_limitable_reflections?(join_dependency.reflections)
           add_lock!(sql, options, scope)
@@ -1714,7 +1718,7 @@ module ActiveRecord
           end
 
           add_conditions!(sql, options[:conditions], scope)
-          add_group!(sql, options[:group], scope)
+          add_group!(sql, options[:group], options[:having], scope)
 
           if order && is_distinct
             connection.add_order_by_for_association_limiting!(sql, :order => order)
diff --git a/activerecord/lib/active_record/associations/association_proxy.rb b/activerecord/lib/active_record/associations/association_proxy.rb
index d1a79df6e6..75ec4fbb2e 100644
--- a/activerecord/lib/active_record/associations/association_proxy.rb
+++ b/activerecord/lib/active_record/associations/association_proxy.rb
@@ -188,6 +188,7 @@ module ActiveRecord
         def merge_options_from_reflection!(options)
           options.reverse_merge!(
             :group   => @reflection.options[:group],
+            :having  => @reflection.options[:having],
             :limit   => @reflection.options[:limit],
             :offset  => @reflection.options[:offset],
             :joins   => @reflection.options[:joins],
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 9e4514375f..8f8ed241d5 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -521,6 +521,7 @@ module ActiveRecord #:nodoc:
       # * <tt>:conditions</tt> - An SQL fragment like "administrator = 1", <tt>[ "user_name = ?", username ]</tt>, or <tt>["user_name = :user_name", { :user_name => user_name }]</tt>. See conditions in the intro.
       # * <tt>:order</tt> - An SQL fragment like "created_at DESC, name".
       # * <tt>:group</tt> - An attribute name by which the result should be grouped. Uses the <tt>GROUP BY</tt> SQL-clause.
+      # * <tt>:having</tt> - Combined with +:group+ this can be used to filter the records that a <tt>GROUP BY</tt> returns. Uses the <tt>HAVING</tt> SQL-clause.
       # * <tt>:limit</tt> - An integer determining the limit on the number of rows that should be returned.
       # * <tt>:offset</tt> - An integer determining the offset from where the rows should be fetched. So at 5, it would skip rows 0 through 4.
       # * <tt>:joins</tt> - Either an SQL fragment for additional joins like "LEFT JOIN comments ON comments.post_id = id" (rarely needed)
@@ -1632,7 +1633,7 @@ module ActiveRecord #:nodoc:
           add_joins!(sql, options[:joins], scope)
           add_conditions!(sql, options[:conditions], scope)
 
-          add_group!(sql, options[:group], scope)
+          add_group!(sql, options[:group], options[:having], scope)
           add_order!(sql, options[:order], scope)
           add_limit!(sql, options, scope)
           add_lock!(sql, options, scope)
@@ -1688,13 +1689,15 @@ module ActiveRecord #:nodoc:
           end
         end
 
-        def add_group!(sql, group, scope = :auto)
+        def add_group!(sql, group, having, scope = :auto)
           if group
             sql << " GROUP BY #{group}"
+            sql << " HAVING #{having}" if having
           else
             scope = scope(:find) if :auto == scope
             if scope && (scoped_group = scope[:group])
               sql << " GROUP BY #{scoped_group}"
+              sql << " HAVING #{scoped_having}" if (scoped_having = scope[:having])
             end
           end
         end
@@ -2259,7 +2262,7 @@ module ActiveRecord #:nodoc:
         end
 
         VALID_FIND_OPTIONS = [ :conditions, :include, :joins, :limit, :offset,
-                               :order, :select, :readonly, :group, :from, :lock ]
+                               :order, :select, :readonly, :group, :having, :from, :lock ]
 
         def validate_find_options(options) #:nodoc:
           options.assert_valid_keys(VALID_FIND_OPTIONS)