1 files changed, 27 insertions, 11 deletions
diff --git a/activerecord/lib/active_record/null_relation.rb b/activerecord/lib/active_record/null_relation.rb
index 711fc8b883..807c301596 100644
--- a/activerecord/lib/active_record/null_relation.rb
+++ b/activerecord/lib/active_record/null_relation.rb
@@ -6,7 +6,7 @@ module ActiveRecord
       @records = []
     end
 
-    def pluck(_column_name)
+    def pluck(*column_names)
       []
     end
 
@@ -23,7 +23,7 @@ module ActiveRecord
     end
 
     def size
-      0
+      calculate :size, nil
     end
 
     def empty?
@@ -39,23 +39,39 @@ module ActiveRecord
     end
 
     def to_sql
-      @to_sql ||= ""
-    end
-
-    def where_values_hash
-      {}
+      ""
     end
 
     def count(*)
-      0
+      calculate :count, nil
     end
 
     def sum(*)
-      0
+      calculate :sum, nil
+    end
+
+    def average(*)
+      calculate :average, nil
+    end
+
+    def minimum(*)
+      calculate :minimum, nil
+    end
+
+    def maximum(*)
+      calculate :maximum, nil
     end
 
-    def calculate(_operation, _column_name, _options = {})
-      nil
+    def calculate(operation, _column_name, _options = {})
+      # TODO: Remove _options argument as soon we remove support to
+      # activerecord-deprecated_finders.
+      if [:count, :sum, :size].include? operation
+        group_values.any? ? Hash.new : 0
+      elsif [:average, :minimum, :maximum].include?(operation) && group_values.any?
+        Hash.new
+      else
+        nil
+      end
     end
 
     def exists?(_id = false)