MySQL-查询获取速度非常慢

因此，我正在尝试加入两个表格-一个是我们平台上的活动报价列表我们是一个汽车租赁比较网站，另一个是定制表格，每天记录每辆车的最佳价格，以及每种可能的财务状况，即9个月的存款价值、24个月的合同和8000英里/年，等等

最终目标是确定什么是“好”价格，输出包含MINoffers.monthly_payment和MINoffers_Lost.Lost_价格，以及计算出的百分比差异，历史价格数据取自7天日期范围，不包括当天

优惠最低是从每日优惠汇总而来的，查找按以下分组的每月最低付款：上限id、存款价值、期限、年里程、财务类型

这就是我到目前为止的想法：

CREATE TABLE `offers` (
  `id` mediumint(8) unsigned NOT NULL auto_increment,
  `cap_id` varchar(255),
  `deposit_value` varchar(255) default NULL,
  `term` varchar(255) default NULL,
  `annual_mileage` varchar(255) default NULL,
  `finance_type` varchar(255) default NULL,
  `monthly_payment` mediumint default NULL,
  `stock` varchar(255) default NULL,
  PRIMARY KEY (`id`)
) AUTO_INCREMENT=1;

INSERT INTO `offers` (`cap_id`,`deposit_value`,`term`,`annual_mileage`,`finance_type`,`monthly_payment`,`stock`) VALUES ("93897","6","24","12000","B",363,"0"),("90626","1","24","12000","P",810,"0"),("93607","6","36","25000","B",172,"1"),("35877","1","48","10000","B",678,"1"),("77134","3","24","10000","P",454,"0"),("47080","6","36","10000","B",737,"0"),("46392","3","24","30000","P",261,"0"),("21418","3","36","20000","B",390,"1"),("80175","9","48","10000","B",713,"1"),("91487","6","48","12000","P",778,"1");
INSERT INTO `offers` (`cap_id`,`deposit_value`,`term`,`annual_mileage`,`finance_type`,`monthly_payment`,`stock`) VALUES ("18311","9","24","20000","B",384,"0"),("41740","9","24","12000","P",674,"1"),("69030","9","24","10000","P",518,"0"),("53342","3","36","8000","B",746,"1"),("65566","6","36","30000","P",145,"1"),("63172","6","48","5000","P",698,"1"),("79712","1","48","30000","B",330,"1"),("90505","1","36","8000","B",458,"0"),("42393","1","36","20000","B",363,"1"),("70454","9","24","5000","B",673,"1");
INSERT INTO `offers` (`cap_id`,`deposit_value`,`term`,`annual_mileage`,`finance_type`,`monthly_payment`,`stock`) VALUES ("81215","1","48","8000","B",472,"0"),("76538","3","24","15000","B",226,"0"),("05094","9","36","12000","P",721,"1"),("57363","9","48","5000","B",777,"1"),("23233","1","48","12000","B",381,"0"),("40542","3","48","12000","P",610,"0"),("63824","3","24","12000","B",761,"1"),("17686","3","24","5000","P",893,"1"),("57669","9","48","30000","P",805,"0"),("21864","1","24","25000","P",530,"0");
INSERT INTO `offers` (`cap_id`,`deposit_value`,`term`,`annual_mileage`,`finance_type`,`monthly_payment`,`stock`) VALUES ("48360","3","48","12000","P",159,"0"),("88614","3","48","20000","B",730,"0"),("17693","1","24","10000","B",298,"0"),("34049","6","48","20000","B",728,"0"),("15038","9","24","10000","P",720,"1"),("31809","1","36","20000","P",237,"0"),("49277","9","48","25000","P",235,"1"),("54607","1","24","12000","P",661,"1"),("65098","1","48","20000","P",548,"1"),("76440","9","48","10000","P",495,"1");

CREATE TABLE `offers_lowest` (
  `id` mediumint(8) unsigned NOT NULL auto_increment,
  `date` DATE,
  `cap_id` varchar(255),
  `deposit` varchar(255) default NULL,
  `term` varchar(255) default NULL,
  `mileage` varchar(255) default NULL,
  `finance_type` varchar(255) default NULL,
  `lowest_price` mediumint default NULL,
  `stock` varchar(255) default NULL,
  PRIMARY KEY (`id`)
) AUTO_INCREMENT=1;

INSERT INTO `offers_lowest` (`date`,`cap_id`,`deposit`,`term`,`mileage`,`finance_type`,`lowest_price`,`stock`) VALUES ("2021-04-09","93897","6","24","12000","B",363,"0"),("2021-04-010","90626","1","24","12000","P",810,"0"),("2021-04-010","93607","6","36","25000","B",172,"1"),("2021-04-10","35877","1","48","10000","B",678,"1"),("2021-04-11","77134","3","24","10000","P",454,"0"),("2021-04-11","47080","6","36","10000","B",737,"0"),("2021-04-11","46392","3","24","30000","P",261,"0"),("2021-04-11","21418","3","36","20000","B",390,"1"),("2021-04-12","80175","9","48","10000","B",713,"1"),("2021-04-12","91487","6","48","12000","P",778,"1");
INSERT INTO `offers_lowest` (`date`,`cap_id`,`deposit`,`term`,`mileage`,`finance_type`,`lowest_price`,`stock`) VALUES ("2021-04-09","18311","9","24","20000","B",384,"0"),("2021-04-010","41740","9","24","12000","P",674,"1"),("2021-04-010","69030","9","24","10000","P",518,"0"),("2021-04-10","53342","3","36","8000","B",746,"1"),("2021-04-11","65566","6","36","30000","P",145,"1"),("2021-04-11","63172","6","48","5000","P",698,"1"),("2021-04-11","79712","1","48","30000","B",330,"1"),("2021-04-11","90505","1","36","8000","B",458,"0"),("2021-04-12","42393","1","36","20000","B",363,"1"),("2021-04-12","70454","9","24","5000","B",673,"1");
INSERT INTO `offers_lowest` (`date`,`cap_id`,`deposit`,`term`,`mileage`,`finance_type`,`lowest_price`,`stock`) VALUES ("2021-04-09","81215","1","48","8000","B",472,"0"),("2021-04-09","76538","3","24","15000","B",226,"0"),("2021-04-010","05094","9","36","12000","P",721,"1"),("2021-04-10","57363","9","48","5000","B",777,"1"),("2021-04-11","23233","1","48","12000","B",381,"0"),("2021-04-11","40542","3","48","12000","P",610,"0"),("2021-04-11","63824","3","24","12000","B",761,"1"),("2021-04-11","17686","3","24","5000","P",893,"1"),("2021-04-12","57669","9","48","30000","P",805,"0"),("2021-04-12","21864","1","24","25000","P",530,"0");
INSERT INTO `offers_lowest` (`date`,`cap_id`,`deposit`,`term`,`mileage`,`finance_type`,`lowest_price`,`stock`) VALUES ("2021-04-09","48360","3","48","12000","P",159,"0"),("2021-04-09","88614","3","48","20000","B",730,"0"),("2021-04-010","17693","1","24","10000","B",298,"0"),("2021-04-10","34049","6","48","20000","B",728,"0"),("2021-04-11","15038","9","24","10000","P",720,"1"),("2021-04-11","31809","1","36","20000","P",237,"0"),("2021-04-11","49277","9","48","25000","P",235,"1"),("2021-04-11","54607","1","24","12000","P",661,"1"),("2021-04-12","65098","1","48","20000","P",548,"1"),("2021-04-12","76440","9","48","10000","P",495,"1");

CREATE INDEX idx_profile_grouping ON offers (cap_id, deposit_value, term, annual_mileage);

CREATE INDEX idx_specials_query ON offers_lowest (cap_id, deposit, term, mileage);

问题在于速度。当我单独运行其中一个子查询时，需要10分钟

这些索引是我在cap_id、存款、期限和里程字段这两个表上创建的，目的是加快速度

解释一下：

身份证件 选择类型 桌子 分割 类型 可能的\u键 钥匙 基伦 裁判 排 过滤 额外的 1. 主要的，重要的 全部的 965741 100 在何处使用；使用临时设备；使用文件排序 1. 主要的，重要的 裁判 10 f、 卡普 f、 存款 f、 术语 f、 里程 3. 衍生 ol 指数 idx\u特价商品\u查询 idx\u特价商品\u查询 13 17386818 5.55 在哪里使用 2. 衍生 o 指数 idx_配置文件_分组 idx_配置文件_分组 10 4800964 50 在哪里使用 从选择。。。加入选择。。。效率低下。尝试将其中至少一个移动到外部选择中。如果为联接添加合适的索引，这可能会避免创建排序索引。它还可以消除大部分神秘的发送数据。 该日期范围仅包括6个日期。 如果一行有MINoffers.monthly\u付款，而另一行有MINoffers\u最低价格，该怎么办？ 不要将VARCHAR255用于数值。例如，里程数中等。这可能会消除将堆转换为ondisk的过程。 请注意如何无用的配置文件；它喜欢说大部分时间发送数据占总数的95%。我可以确定4%，并建议修复，见上文。另外1%是不可避免的噪音。 第一个GROUP BY是不合适的，因为它没有说明股票或品牌id的值。如果必要，在找到其余信息后，用额外的连接抓住它们。 提供最低需求指数财务类型、日期 摆脱索引提示使用索引。。。

---

@草莓看小提琴，谢谢！非常感谢您的详细回复-关于finance_type，date的索引-我应该修改原始索引以包括这两个，还是可以用这些列创建一个单独的索引？@AlexMidmore-是的，修改现有索引。在添加INDEXa，b时，删除INDEXa。我还注意到在加入“brands”表时出现的一个问题-b.name brand name的输出对于每一行都是相同的，这表明它没有正确地加入，但我不明白why@AlexMidmore-我认为您需要以问题中的查询开始一个新问题，并显示CREATE TABLE brand和EXPLAIN SELECT…，以及一些数据来显示问题。

SELECT 
    s.cap_id,
    s.deposit,
    s.term,
    s.mileage,
    s.best_price,
    f.previous_best,
    (( s.best_price - f.previous_best ) / f.previous_best ) * 100 AS difference,
    s.stock
FROM
    (SELECT
        o.cap_id,
        o.deposit_value as deposit,
        o.term,
        o.annual_mileage as mileage,
        o.finance_type,
        MIN(o.monthly_payment) AS best_price,
        o.stock,
        o.brand_id
    FROM
        offers o USE INDEX(idx_profile_grouping)
    WHERE o.finance_type = 'P'
    GROUP BY o.cap_id, o.deposit_value, o.term, o.annual_mileage
    ) s 
    
INNER JOIN

    (SELECT
        ol.cap_id,
        ol.deposit,
        ol.term,
        ol.mileage,
        MIN(lowest_price) as previous_best
    FROM
        offers_lowest ol USE INDEX(idx_specials_query)
    WHERE finance_type = 'P'
        AND ol.date > CURDATE() - INTERVAL 7 DAY
        AND ol.date <= CURDATE() - INTERVAL 1 DAY
    GROUP BY ol.cap_id, ol.deposit, ol.term, ol.mileage
    ) f ON s.cap_id = f.cap_id AND s.deposit = f.deposit AND s.term = f.term AND s.mileage = f.mileage
GROUP BY s.cap_id, s.deposit, s.term, s.mileage