{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "17.25"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "num",
          "access_type": "ALL",
          "rows_examined_per_scan": 5,
          "rows_produced_per_join": 5,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "10.25",
            "eval_cost": "1.00",
            "prefix_cost": "11.25",
            "data_read_per_join": "120"
          },
          "used_columns": [
            "lot_id",
            "participants_count"
          ],
          "materialized_from_subquery": {
            "using_temporary_table": true,
            "dependent": false,
            "cacheable": true,
            "query_block": {
              "select_id": 2,
              "cost_info": {
                "query_cost": "83.50"
              },
              "grouping_operation": {
                "using_temporary_table": true,
                "using_filesort": true,
                "nested_loop": [
                  {
                    "table": {
                      "table_name": "temp",
                      "access_type": "index",
                      "possible_keys": [
                        "PRIMARY"
                      ],
                      "key": "PRIMARY",
                      "used_key_parts": [
                        "ab_id"
                      ],
                      "key_length": "4",
                      "rows_examined_per_scan": 55,
                      "rows_produced_per_join": 55,
                      "filtered": "100.00",
                      "using_index": true,
                      "cost_info": {
                        "read_cost": "1.00",
                        "eval_cost": "11.00",
                        "prefix_cost": "12.00",
                        "data_read_per_join": "440"
                      },
                      "used_columns": [
                        "ab_id"
                      ]
                    }
                  },
                  {
                    "table": {
                      "table_name": "ab",
                      "access_type": "eq_ref",
                      "possible_keys": [
                        "PRIMARY",
                        "lot_id"
                      ],
                      "key": "PRIMARY",
                      "used_key_parts": [
                        "id"
                      ],
                      "key_length": "4",
                      "ref": [
                        "test.temp.ab_id"
                      ],
                      "rows_examined_per_scan": 1,
                      "rows_produced_per_join": 5,
                      "filtered": "10.00",
                      "cost_info": {
                        "read_cost": "55.00",
                        "eval_cost": "1.10",
                        "prefix_cost": "78.00",
                        "data_read_per_join": "4K"
                      },
                      "used_columns": [
                        "id",
                        "lot_id",
                        "status"
                      ],
                      "attached_condition": "(`test`.`ab`.`status` = 1)"
                    }
                  }
                ]
              }
            }
          }
        }
      },
      {
        "table": {
          "update": true,
          "table_name": "filter",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "lot_id",
            "lot_type"
          ],
          "key_length": "8",
          "ref": [
            "num.lot_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 5,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "5.00",
            "eval_cost": "1.00",
            "prefix_cost": "17.25",
            "data_read_per_join": "80"
          },
          "used_columns": [
            "lot_id",
            "lot_type",
            "participants_count"
          ]
        }
      }
    ]
  }
}