diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index c445ec15dd9f5c1e492599cbfe5817ec52ee4f1a..172026d1507ea60bdd23c332bddbce6a633837ac 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -149,9 +149,9 @@ def attribute_names
 
     # Returns a hash of all the attributes with their names as keys and the values of the attributes as values.
     def attributes
-      attrs = {}
-      attribute_names.each { |name| attrs[name] = read_attribute(name) }
-      attrs
+      attribute_names.each_with_object({}) { |name, attrs|
+        attrs[name] = read_attribute(name)
+      }
     end
 
     # Returns an <tt>#inspect</tt>-like string for the value of the
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
index cb8f9034749adbcb0f07ac6d0eb986ff918f6c8c..a240c137ea38c04275669f3bef196b59fa3a998d 100644
--- a/activerecord/lib/active_record/relation/predicate_builder.rb
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -4,7 +4,7 @@ def self.build_from_hash(engine, attributes, default_table)
       attributes.map do |column, value|
         table = default_table
 
-        if value.is_a?(Hash)
+        if value.is_a?(Hash) && !value.empty?
           table = Arel::Table.new(column, engine)
           value.map { |k,v| build(table[k.to_sym], v) }
         else