2 files changed, 8 insertions, 11 deletions
diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index ccb48247b7..4becf3980d 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -207,15 +207,18 @@ module ActiveRecord
       end
 
       if operation == "count"
-        column_name ||= (select_for_count || :all)
+        if select_values.present?
+          column_name ||= select_values.join(", ")
+        else
+          column_name ||= :all
+        end
 
         unless arel.ast.grep(Arel::Nodes::OuterJoin).empty?
           distinct = true
         end
 
         column_name = primary_key if column_name == :all && distinct
-
-        distinct = nil if column_name =~ /\s*DISTINCT\s+/i
+        distinct = nil if column_name =~ /\s*DISTINCT[\s(]+/i
       end
 
       if group_values.any?
@@ -376,13 +379,6 @@ module ActiveRecord
       column ? column.type_cast(value) : value
     end
 
-    def select_for_count
-      if select_values.present?
-        select = select_values.join(", ")
-        select if select !~ /[,*]/
-      end
-    end
-
     def build_count_subquery(relation, column_name, distinct)
       column_alias = Arel.sql('count_column')
       subquery_alias = Arel.sql('subquery_for_count')
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index f0edef58bf..cbb2803593 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -172,7 +172,8 @@ module ActiveRecord
         relation = relation.where(table[primary_key].eq(conditions)) if conditions != :none
       end
 
-      connection.select_value(relation, "#{name} Exists", relation.bind_values)
+      relation = relation.with_default_scope
+      connection.select_value(relation.arel, "#{name} Exists", relation.bind_values)
     end
 
     # This method is called whenever no records are found with either a single