Question

国家/地区表大约有2条记录。
状态表大约有50条记录。
城市表中大约有6000条记录。
邮政编码表大约有500000条记录

提取数据大约需要12-15分钟。

如何优化以下查询：

SELECT Country.id          AS Country_id, 
       Country.country     AS Country_country, 
       Country.countrycode AS Country_countrycode, 
       State.id            AS State_id, 
       State.statecode     AS State_statecode, 
       City.id             AS City_id, 
       City.city           AS City_city, 
       Zipcode.id          AS Zipcode_id, 
       Zipcode.zipcode     AS Zipcode_zipcode 
FROM   c_country Country 
       LEFT JOIN c_state State 
              ON Country.id = ( State.country_id ) 
       LEFT JOIN c_city City 
              ON State.id = ( City.state_id ) 
       LEFT JOIN c_zipcode Zipcode 
              ON City.id = ( Zipcode.city_id )

以下是表格结构：

CREATE TABLE `c_city` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `state_id` int(11) NOT NULL,
  `city` varchar(256) NOT NULL,
  `zone_id` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=7027 DEFAULT CHARSET=latin1;

CREATE TABLE `c_state` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `country_id` int(11) NOT NULL,
  `state` varchar(256) NOT NULL,
  `statecode` varchar(256) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=latin1;

CREATE TABLE `c_country` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `country` varchar(256) NOT NULL,
  `countrycode` varchar(256) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1;

CREATE TABLE `c_zipcode` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `city_id` int(11) NOT NULL,
  `zipcode` varchar(256) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=539420 DEFAULT CHARSET=latin1;

下面是EXPLAIN SELECT的屏幕截图：

Answer 1

要尝试提高性能，您可以为

添加索引

table c_zipcode  column  city_id
table c_city column  state_id 
table  c_state column  country_id

或用于使用索引

解析所有列值

table c_zipcode  column  city_id, zipcode
table c_city column  state_id, city
table  c_state column  country_id , statecode

Answer 2

我认为您的查询非常慢，因为缺少一些索引。您没有声明任何外键，在mysql InnoDB中，外键很重要，因为它们是数据完整性的保证，但MySQL也会在此外键上自动创建索引。

说明链接：https://dba.stackexchange.com/questions/105469/performance-impact-of-adding-a-foreign-key-to-a-1m-rows-table

您必须更改表以添加外键：

.PactUri(@"..\..\..\..\pacts")

.PactUri(@"..\..\..\..\pacts\*.json")

如何优化与区域相关的MYSQL查询

2 个答案: