1 files changed, 9 insertions, 1 deletions
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb
index e21ef90391..67631f0120 100644
--- a/activerecord/lib/active_record/associations/has_many_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -90,7 +90,15 @@ module ActiveRecord
               @finder_sql = construct_conditions
           end
 
-          construct_counter_sql
+          if @reflection.options[:counter_sql]
+            @counter_sql = interpolate_sql(@reflection.options[:counter_sql])
+          elsif @reflection.options[:finder_sql]
+            # replace the SELECT clause with COUNT(*), preserving any hints within /* ... */
+            @reflection.options[:counter_sql] = @reflection.options[:finder_sql].sub(/SELECT (\/\*.*?\*\/ )?(.*)\bFROM\b/im) { "SELECT #{$1}COUNT(*) FROM" }
+            @counter_sql = interpolate_sql(@reflection.options[:counter_sql])
+          else
+            @counter_sql = @finder_sql
+          end
         end
 
         def has_cached_counter?