Mysql 当只更改WHERE子句值时，为什么查询运行速度要慢近100倍？

我有以下疑问：

SELECT count(m.p1_elo_one)
FROM belgarath.match_result as m
INNER JOIN belgarath.tournament AS tm ON tm.id_ = m.tournament_id
INNER JOIN belgarath.tour AS tr ON tr.id_ = tm.tour_id
INNER JOIN belgarath.rank AS rk ON rk.id_ = tm.rank_id
INNER JOIN belgarath.round AS rd ON rd.id_ = m.round_id
INNER JOIN belgarath.parameters_match AS pm
    ON pm.tour_id = tm.tour_id
    AND pm.rank_id = tm.rank_id
    AND pm.round_id = m.round_id
INNER JOIN belgarath.surf ON belgarath.surf.id_ = tm.surf
INNER JOIN belgarath.player AS p ON p.id_ = m.p1_id 
WHERE 
    belgarath.surf.surf_std_id = 1
    AND pm.engineer = 1
    AND m.date_time_inferred < "2003-06-01"
    AND m.date_time_inferred > "2000-06-01"
    AND m.p1_elo_one IS NOT NULL
    AND p.name_ NOT LIKE "%/%"

解释

查询：

---

是否有任何或所有WHERE子句列被索引？请注意，rank现在是一个保留字，这使得它作为表/列标识符的选择很糟糕（令人惊讶的是，ROUND并没有保留）@GilbertLeBlanc-嘿。所有WHERE子句列都被编入索引，除了最后两列：

m.p1\u elo\u one

（Float）和

p.name

（VARCHAR）@草莓-我已经停止了

SHOW CREATE TABLE

，因为有太多的表和列。我想知道症状是否表明了一些明显的东西？我现在就把

EXPLAIN

放上去-那对我来说是一个新的！感谢大家对

排名的提醒

——我也注意到了……嗯，我要修改

ix\u belgarath\u match\u date\u time\u推断

，包括

p1\u elo\u one

——并在（

巡演id，排名id，轮号，工程师

）的一些排列上粘贴一个索引。但也许其他人有更好的想法。

'CREATE TABLE `match_result` (
  `id_` int NOT NULL AUTO_INCREMENT,
  `date_time_op_scheduled` datetime DEFAULT NULL,
  `date_time_op_actual` datetime DEFAULT NULL,
  `date_time_oc_actual` datetime DEFAULT NULL,
  `date_time_inferred` datetime DEFAULT NULL,
  `tournament_id` int DEFAULT NULL,
  `round_id` tinyint DEFAULT NULL,
  `p1_id` int DEFAULT NULL,
  `p2_id` int DEFAULT NULL,
  `result` varchar(45) DEFAULT NULL,
  `uncertainty` float DEFAULT NULL,
  `uncertainty_bin` int DEFAULT NULL,
  `p1_win_pred` float DEFAULT NULL,
  `p1_win_SD` float DEFAULT NULL,
  `url` varchar(255) DEFAULT NULL,
  `winning_player` int DEFAULT NULL,
  `completed_sets` int DEFAULT NULL,
  `result_type_id` int DEFAULT NULL,
  `p1_pinnacle_closing_odds` float DEFAULT NULL,
  `p2_pinnacle_closing_odds` float DEFAULT NULL,
  `post_match_data_retrieved` int DEFAULT NULL,
  `p1_elo_all` float DEFAULT NULL,
  `p1_elo_exc_ret_all` float DEFAULT NULL,
  `p1_h2h_win_one_time` float DEFAULT NULL,
  `p1_h2h_win_one_none` int DEFAULT NULL,
  `p1_h2h_win_all_time_surf` float DEFAULT NULL,
  `p1_h2h_win_all_surf` float DEFAULT NULL,
  `p1_h2h_win_all_time` float DEFAULT NULL,
  `p1_h2h_win_all_none` int DEFAULT NULL,
  `p1_h2h_one_time` float DEFAULT NULL,
  `p1_h2h_one_none` int DEFAULT NULL,
  `p1_h2h_all_time_surf` float DEFAULT NULL,
  `p1_h2h_all_surf` float DEFAULT NULL,
  `p1_h2h_all_time` float DEFAULT NULL,
  `p1_h2h_all_none` int DEFAULT NULL,
  `p1_win_one_time` float DEFAULT NULL,
  `p1_win_one_none` int DEFAULT NULL,
  `p1_win_all_time_surf` float DEFAULT NULL,
  `p1_win_all_surf` float DEFAULT NULL,
  `p1_win_all_time` float DEFAULT NULL,
  `p1_win_all_none` int DEFAULT NULL,
  `p1_match_one_time` float DEFAULT NULL,
  `p1_match_one_none` int DEFAULT NULL,
  `p1_match_all_time_surf` float DEFAULT NULL,
  `p1_match_all_surf` float DEFAULT NULL,
  `p1_match_all_time` float DEFAULT NULL,
  `p1_match_all_none` int DEFAULT NULL,
  `p1_elo_one` float DEFAULT NULL,
  `p1_elo_exc_ret_one` float DEFAULT NULL,
  `p1_jet_lag` float DEFAULT NULL,
  `p1_fatigue_short_term` int DEFAULT NULL,
  `p1_fatigue_long_term` int DEFAULT NULL,
  `p1_retired_last_match` tinyint DEFAULT NULL,
  `p2_elo_all` float DEFAULT NULL,
  `p2_elo_exc_ret_all` float DEFAULT NULL,
  `p2_h2h_win_one_time` float DEFAULT NULL,
  `p2_h2h_win_one_none` int DEFAULT NULL,
  `p2_h2h_win_all_time_surf` float DEFAULT NULL,
  `p2_h2h_win_all_surf` float DEFAULT NULL,
  `p2_h2h_win_all_time` float DEFAULT NULL,
  `p2_h2h_win_all_none` int DEFAULT NULL,
  `p2_h2h_one_time` float DEFAULT NULL,
  `p2_h2h_one_none` int DEFAULT NULL,
  `p2_h2h_all_time_surf` float DEFAULT NULL,
  `p2_h2h_all_surf` float DEFAULT NULL,
  `p2_h2h_all_time` float DEFAULT NULL,
  `p2_h2h_all_none` int DEFAULT NULL,
  `p2_win_one_time` float DEFAULT NULL,
  `p2_win_one_none` int DEFAULT NULL,
  `p2_win_all_time_surf` float DEFAULT NULL,
  `p2_win_all_surf` float DEFAULT NULL,
  `p2_win_all_time` float DEFAULT NULL,
  `p2_win_all_none` int DEFAULT NULL,
  `p2_match_one_time` float DEFAULT NULL,
  `p2_match_one_none` int DEFAULT NULL,
  `p2_match_all_time_surf` float DEFAULT NULL,
  `p2_match_all_surf` float DEFAULT NULL,
  `p2_match_all_time` float DEFAULT NULL,
  `p2_match_all_none` int DEFAULT NULL,
  `p2_elo_one` float DEFAULT NULL,
  `p2_elo_exc_ret_one` float DEFAULT NULL,
  `p2_jet_lag` float DEFAULT NULL,
  `p2_fatigue_short_term` int DEFAULT NULL,
  `p2_fatigue_long_term` int DEFAULT NULL,
  `p2_retired_last_match` tinyint DEFAULT NULL,
  `engineered` tinyint DEFAULT NULL,
  `updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  `created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id_`),
  KEY `ix_belgarath_match__completed_sets` (`completed_sets`),
  KEY `ix_belgarath_match__post_match_data_retrieved` (`post_match_data_retrieved`),
  KEY `ix_belgarath_match__date_time_oc_actual` (`date_time_oc_actual`),
  KEY `ix_belgarath_match__tournament_id` (`tournament_id`),
  KEY `ix_belgarath_match__round_id` (`round_id`),
  KEY `ix_belgarath_match__player_id_2` (`p2_id`),
  KEY `ix_belgarath_match__winning_player` (`winning_player`),
  KEY `ix_belgarath_match__result_type_id` (`result_type_id`),
  KEY `ix_belgarath_match__uncertainty_bin` (`uncertainty_bin`),
  KEY `ix_belgarath_match__date_time_inferred` (`date_time_inferred`),
  KEY `ix_belgarath_match__date_time_op_actual` (`date_time_op_actual`),
  KEY `ix_belgarath_match__player_id_1` (`p1_id`),
  KEY `ix_belgarath_match__date_time_op_scheduled` (`date_time_op_scheduled`) /*!80000 INVISIBLE */,
  KEY `ix_belgarath_match__engineered` (`engineered`),
  CONSTRAINT `match_result__player_1` FOREIGN KEY (`p1_id`) REFERENCES `player` (`id_`),
  CONSTRAINT `match_result__player_2` FOREIGN KEY (`p2_id`) REFERENCES `player` (`id_`),
  CONSTRAINT `match_result__round` FOREIGN KEY (`round_id`) REFERENCES `round` (`id_`),
  CONSTRAINT `match_result__tournament` FOREIGN KEY (`tournament_id`) REFERENCES `tournament` (`id_`)
) ENGINE=InnoDB AUTO_INCREMENT=1408022 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci'