diff options
| -rw-r--r-- | activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb index f8c9e13392..b9a9c22198 100644 --- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb @@ -965,11 +965,13 @@ module ActiveRecord subsubselect = select.clone subsubselect.projections = [key] + # Materialize subquery by adding distinct + # to work with MySQL 5.7.6 which sets optimizer_switch='derived_merge=on' + subsubselect.distinct unless select.limit || select.offset || select.orders.any? + subselect = Arel::SelectManager.new(select.engine) subselect.project Arel.sql(key.name) - # Materialized subquery by adding distinct - # to work with MySQL 5.7.6 which sets optimizer_switch='derived_merge=on' - subselect.from subsubselect.distinct.as('__active_record_temp') + subselect.from subsubselect.as('__active_record_temp') end def mariadb? |