has_and_belongs_to_many: use JOIN instead of LEFT JOIN. References #2937.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3155 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

2 files changed, 4 insertions, 2 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 1941ce1ef6..f3c2a4ea7c 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* has_and_belongs_to_many: use JOIN instead of LEFT JOIN.  [Jeremy Kemper]
+
 * MySQL: introduce :encoding option to specify the character set for client, connection, and results.  Only available for MySQL 4.1 and later with the mysql-ruby driver.  Do SHOW CHARACTER SET in mysql client to see available encodings.  #2975 [Shugo Maeda]
 
 * Add tasks to create, drop and rebuild the MySQL and PostgreSQL test  databases. [Marcel Molina Jr.]
diff --git a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
index 2a51efb94f..4bfa759666 100644
--- a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
@@ -154,8 +154,8 @@ module ActiveRecord
             @finder_sql = "#{@join_table}.#{@association_class_primary_key_name} = #{@owner.quoted_id} "
             @finder_sql << " AND (#{interpolate_sql(@options[:conditions])})" if @options[:conditions]
           end
-          
-          @join_sql = "LEFT JOIN #{@join_table} ON #{@association_class.table_name}.#{@association_class.primary_key} = #{@join_table}.#{@association_foreign_key}"
+
+          @join_sql = "JOIN #{@join_table} ON #{@association_class.table_name}.#{@association_class.primary_key} = #{@join_table}.#{@association_foreign_key}"
         end
         
     end