method

join_to_update

v5.0.0.1 - Show latest stable - Class: ActiveRecord::ConnectionAdapters

join_to_update(update, select, key)

public

In the simple case, MySQL allows us to place JOINs directly into the UPDATE query. However, this does not allow for LIMIT, OFFSET and ORDER. To support these, we must use a subquery.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 248
      def join_to_update(update, select, key) # :nodoc:
        if select.limit || select.offset || select.orders.any?
          super
        else
          update.table select.source
          update.wheres = select.constraints
        end
      end

join_to_update

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