maia · June 15, 2009 16:06 · Jun 15, 2009
diff --git a/ActiveRecord::Base.select_values b/ActiveRecord::Base.select_values
@@ -0,0 +1,82 @@
+class ActiveRecord::Base
+
+  class << self
+
+    def select_values(*args)
+      options = args.extract_options!
+      validate_find_options(options)
+      set_readonly_option!(options)
+      raise "select_values does not support the :include option" if options[:include]
+
+      sql = construct_finder_sql(options)
+      select_values_by_sql(options[:select].to_s, sql)
+    end
+
+    def select_value(*args)
+      options = args.extract_options!
+      validate_find_options(options)
+      set_readonly_option!(options)
+      raise "select_values does not support the :include option" if options[:include]
+
+      sql = construct_finder_sql(options.update(:limit => 1))
+      select_values_by_sql(options[:select].to_s, sql).first
+    end
+
+    def select_all(*args)
+      options = args.extract_options!
+      validate_find_options(options)
+      set_readonly_option!(options)
+      raise "select_values does not support the :include option" if options[:include]
+
+      sql = construct_finder_sql(options)
+      select_all_by_sql(sql)
+    end
+
+    def select_rows(*args)
+      options = args.extract_options!
+      validate_find_options(options)
+      set_readonly_option!(options)
+      raise "select_rows does not support the :include option" if options[:include]
+
+      sql = construct_finder_sql(options)
+      columns = options[:select].split(',').map(&:strip)
+      columns = columns.map do |column|
+        column.include?(" AS ") ? column[/AS (.+)/][3..-1] : column
+      end
+      select_rows_by_sql(columns, sql)
+    end
+
+    private
+
+    def select_values_by_sql(column_name, sql)
+      result = connection.select_values(sanitize_sql(sql))
+      column = columns_hash[column_name]
+      column ? result.map {|val| column.type_cast(val) } : result
+    end
+
+    def select_all_by_sql(sql)
+      result = connection.select_all(sanitize_sql(sql))
+      result.collect do |record|
+        record.inject({}) do |memo, kv|
+          column = self.columns_hash[kv[0]]
+          memo[kv[0]] = column ? column.type_cast(kv[1]) : kv[1]
+          memo
+        end
+      end
+    end
+
+    def select_rows_by_sql(columns, sql)
+      result = connection.select_rows(sanitize_sql(sql))
+      result.collect do |record|
+        row = []
+        record.each_with_index do |value, index|
+          column = self.columns_hash[columns[index]]
+          row << (column ? column.type_cast(value) : value)
+        end
+        row
+      end
+    end
+
+  end
+
+end