Use Arel::Attribute when building where conditions from hash

activerecord/lib/active_record/relation/query_methods.rb

@@ -104,14 +104,16 @@ def joins(join, join_type = nil)
     def where(*args)
       return spawn if args.blank?
 
-      if [String, Hash, Array].include?(args.first.class)
-        conditions = @klass.send(:merge_conditions, args.size > 1 ? Array.wrap(args) : args.first)
-        conditions = Arel::SqlLiteral.new(conditions) if conditions
+      conditions = if [String, Array].include?(args.first.class)
+        merged = @klass.send(:merge_conditions, args.size > 1 ? Array.wrap(args) : args.first)
+        Arel::SqlLiteral.new(merged) if merged
+      elsif args.first.is_a?(Hash)
+        build_predicate_from_hash(args.first)
       else
-        conditions = args.first
+        args.first
       end
 
-      spawn(@relation.where(conditions))
+      spawn(@relation.where(*conditions))
     end
 
     private
@@ -128,5 +130,34 @@ def reverse_sql_order(order_query)
       }.join(',')
     end
 
+    def build_predicate_from_hash(attributes, default_table = self.table)
+      attributes = @klass.send(:expand_hash_conditions_for_aggregates, attributes)
+
+      predicates = attributes.map do |column, value|
+        arel_table = default_table
+
+        if value.is_a?(Hash)
+          arel_table = Arel::Table.new(column, Arel::Sql::Engine.new(@klass))
+          build_predicate_from_hash(value, arel_table)
+        else
+          column = column.to_s
+
+          if column.include?('.')
+            table_name, column = column.split('.', 2)
+            arel_table = Arel::Table.new(table_name, Arel::Sql::Engine.new(@klass))
+          end
+
+          case value
+          when Array, Range, ActiveRecord::Associations::AssociationCollection, ActiveRecord::NamedScope::Scope
+            arel_table[column].in(value)
+          else
+            arel_table[column].eq(value)
+          end
+        end
+      end
+
+      predicates.flatten
+    end
+
   end
 end