MariaDB [dbt3]> explain format=json SELECT *    FROM      t      JOIN nation  ON (t.a = nation.n_nationkey)      LEFT JOIN region ON ( r_regionkey = n_regionkey )     JOIN supplier ON ( s_nationkey = n_nationkey )     JOIN partsupp ON ( s_suppkey = ps_suppkey )      JOIN lineitem ON ( ps_partkey = l_partkey )      JOIN orders ON ( l_orderkey = o_orderkey )      JOIN customer    WHERE o_totalprice = 151 OR c_nationkey = s_nationkey AND s_acctbal > 187\G
*************************** 1. row ***************************
EXPLAIN: {
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "supplier",
          "access_type": "system",
          "possible_keys": ["PRIMARY"],
          "rows": 1,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "nation",
          "access_type": "const",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "4",
          "used_key_parts": ["n_nationkey"],
          "ref": ["const"],
          "rows": 1,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "region",
          "access_type": "const",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "4",
          "used_key_parts": ["r_regionkey"],
          "ref": ["const"],
          "rows": 1,
          "filtered": 100,
          "using_index": true
        }
      },
      {
        "table": {
          "table_name": "lineitem",
          "access_type": "ALL",
          "possible_keys": ["PRIMARY"],
          "rows": 3,
          "filtered": 100,
          "attached_condition": "lineitem.l_partkey is not null"
        }
      },
      {
        "table": {
          "table_name": "partsupp",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "8",
          "used_key_parts": ["ps_partkey", "ps_suppkey"],
          "ref": ["dbt3.lineitem.l_partkey", "const"],
          "rows": 1,
          "filtered": 100,
          "using_index": true
        }
      },
      {
        "table": {
          "table_name": "orders",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "4",
          "used_key_parts": ["o_orderkey"],
          "ref": ["dbt3.lineitem.l_orderkey"],
          "rows": 1,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "customer",
          "access_type": "index",
          "possible_keys": ["i_c_nationkey"],
          "key": "i_c_nationkey",
          "key_length": "5",
          "used_key_parts": ["c_nationkey"],
          "rows": 3,
          "filtered": 100,
          "attached_condition": "orders.o_totalprice = 151 or customer.c_nationkey = 17",
          "using_index": true
        }
      },
      {
        "table": {
          "table_name": "t",
          "access_type": "ALL",
          "rows": 4,
          "filtered": 100,
          "attached_condition": "t.a = 17 and (orders.o_totalprice = 151 or customer.c_nationkey = 17 and t.a = 17)"
        }
      }
    ]
  }
}