1. id select_type table type possible_keys key key_len ref rows Extra
  2. 1 PRIMARY <derived2> system NULL NULL NULL NULL 1 "Using filesort"
  3. 1 PRIMARY <derived3> system NULL NULL NULL NULL 1
  4. 1 PRIMARY my_table ALL NULL NULL NULL NULL 32594440
  5. 3 DERIVED NULL NULL NULL NULL NULL NULL NULL "No tables used"
  6. 2 DERIVED NULL NULL NULL NULL NULL NULL NULL "No tables used"