primary_keys

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 596
      def primary_keys(table_name) # :nodoc:
        raise ArgumentError unless table_name.present?

        scope = quoted_scope(table_name)

        query_values(<<~SQL, "SCHEMA")
          SELECT column_name
          FROM information_schema.statistics
          WHERE index_name = 'PRIMARY'
            AND table_schema = #{scope[:schema]}
            AND table_name = #{scope[:name]}
          ORDER BY seq_in_index
        SQL
      end