Added AbstractAdapter#select_value and AbstractAdapter#select_values as convenience methods for selecting single values, instead of hashes, of the first column in a SELECT #2283

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2323 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 13 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index a1a71afb5b..fed51fea18 100755
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -275,6 +275,19 @@ module ActiveRecord
       # Returns a record hash with the column names as a keys and fields as values.
       def select_one(sql, name = nil) end
 
+      # Returns a single value from a record
+      def select_value(sql, name = nil)
+        result = select_one(sql, name)
+        result.nil? ? nil : result.values.first
+      end
+
+      # Returns an array of the values of the first column in a select:
+      #   select_values("SELECT id FROM companies LIMIT 3") => [1,2,3]
+      def select_values(sql, name = nil)
+        result = select_all(sql, name)
+        result.map{ |v| v.values.first }
+      end
+
       # Returns an array of table names for the current database.
       # def tables(name = nil) end