MySQL 多表連接
[英]MySQL multiple table joins
問題描述
一、介紹
我正在建立一個支持系統，來自某個國家/地區的用戶提出某個類別的問題，來自該國家、行政部門和類別的專家被分配該問題。
來自Germany的前用戶 zip 代碼1000在Software類別上出現問題。 來自Germany國家和/或 zip 代碼邊界MIN_PROVINCE_ZIPCODE <= 1000 >= MAX_PROVINCE_ZIPCODE的省份和/或Software代碼邊界MIN_REGION_ZIPCODE <= 1000 >= MAX_REGION_ZIPCODE <= 1000 和/或區域的專家
Ie: Select all issues where issue country is equal to expert country, and issue category is equal to one of experts' categories, and/or issue zip code is greater or equal to minimum province zip code and smaller or equal to maximum province zip code , 和/或發布 zip 代碼大於或等於區域最小值 zip 代碼並且發布代碼小於或等於 zip 代碼。
“和/或”是指是否指派專家處理特定行政部門的問題，如果不是，則指派與他們的國家和類別相匹配的所有內容
二、 數據庫模式和記錄
*記住！*
a) 專家可以參與...
- 一個、多個或無類別
- 一個、多個或沒有省份
- 一個、多個或無區域
b) 如果專家不是...
- 一個類別，那么不會分配給他們任何問題
- 一個省，那么他們國家和類別的所有問題都將分配給他們
- 一個地區，那么他們省份的所有問題都將分配給他們
1. 模式
CREATE TABLE IF NOT EXISTS `categories` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(300) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `provinces` (
`id` bigint(11) unsigned NOT NULL AUTO_INCREMENT,
`country` varchar(300) NOT NULL,
`province` varchar(300) NOT NULL,
`min_zipcode` int(5) unsigned NOT NULL,
`max_zipcode` int(5) unsigned NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `regions` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`provinceid` int(11) unsigned NOT NULL,
`region` varchar(300) NOT NULL,
`min_zipcode` int(5) unsigned NOT NULL,
`max_zipcode` int(5) unsigned NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `issues` (
`id` bigint(11) unsigned NOT NULL AUTO_INCREMENT,
`categoryid` int(11) unsigned NOT NULL,
`country` varchar(150) NOT NULL,
`zipcode` int(5) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `experts` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`country` varchar(150) NOT NULL DEFAULT 'none',
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `experts_categories` (
`expertid` int(11) unsigned NOT NULL,
`categoryid` int(11) unsigned NOT NULL,
PRIMARY KEY (`expertid`,`categoryid`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `experts_provinces` (
`expertid` int(11) unsigned NOT NULL,
`provinceid` int(11) unsigned NOT NULL,
PRIMARY KEY (`expertid`,`provinceid`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `experts_regions` (
`expertid` int(11) NOT NULL,
`regionid` int(11) NOT NULL,
PRIMARY KEY (`expertid`,`regionid`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
2. 記錄
INSERT INTO `categories` (`id`, `name`) VALUES
(1, 'Software'),
(2, 'Hardware');
INSERT INTO `experts` (`id`, `country`) VALUES
(1, 'Germany'),
(2, 'France'),
(3, 'Germany');
INSERT INTO `experts_categories` (`expertid`, `categoryid`) VALUES
(1, 1),
(1, 2),
(2, 1),
(3, 1);
INSERT INTO `experts_provinces` (`expertid`, `provinceid`) VALUES
(1, 4),
(2, 6),
(2, 7);
INSERT INTO `experts_regions` (`expertid`, `regionid`) VALUES
(1, 8),
(1, 10);
INSERT INTO `issues` (`id`, `categoryid`, `country`, `zipcode`) VALUES
(1, 2, 'Germany', 2100),
(2, 1, 'France', 1900),
(3, 1, 'Germany', 1500),
(4, 2, 'Germany', 2800),
(5, 2, 'France', 1850);
INSERT INTO `provinces` (`id`, `country`, `province`, `min_zipcode`, `max_zipcode`) VALUES
(1, 'Germany', 'Province One', 1000, 1299),
(2, 'Germany', 'Province Two', 1300, 1499),
(3, 'Germany', 'Province Three', 1500, 1999),
(4, 'Germany', 'Province Four', 2000, 2899),
(5, 'France', 'Province One', 1000, 1799),
(6, 'France', 'Province Two', 1800, 2199),
(7, 'France', 'Province Three', 2200, 2399);
INSERT INTO `regions` (`id`, `provinceid`, `region`, `min_zipcode`, `max_zipcode`) VALUES
(1, 1, 'Region One', 1000, 1099),
(2, 1, 'Region Two', 1100, 1159),
(3, 1, 'Region Three', 1160, 1299),
(4, 2, 'Region One', 1300, 1400),
(5, 2, 'Region Two', 1401, 1499),
(6, 3, 'Region One', 1500, 1699),
(7, 3, 'Region Two', 1700, 1999),
(8, 4, 'Region One', 2000, 2299),
(9, 4, 'Region Two', 2300, 2599),
(10, 4, 'Region Three', 2600, 2699),
(11, 4, 'Region Four', 2700, 2899),
(12, 5, 'Region One', 1000, 1699),
(13, 5, 'Region Two', 1700, 1799),
(14, 6, 'Region One', 1800, 2000),
(15, 6, 'Region Two', 2001, 2199),
(16, 7, 'Region One', 2200, 2299),
(17, 7, 'Region Two', 2300, 2399);
3. 視覺模式
mysql> DESC `categories`;
+-------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+------------------+------+-----+---------+----------------+
| id | int(11) unsigned | NO | PRI | NULL | auto_increment |
| name | varchar(300) | NO | | NULL | |
+-------+------------------+------+-----+---------+----------------+
mysql> DESC `provinces`;
+-------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+---------------------+------+-----+---------+----------------+
| id | bigint(11) unsigned | NO | PRI | NULL | auto_increment |
| country | varchar(300) | NO | | NULL | |
| province | varchar(300) | NO | | NULL | |
| min_zipcode | int(5) unsigned | NO | | NULL | |
| max_zipcode | int(5) unsigned | NO | | NULL | |
+-------------+---------------------+------+-----+---------+----------------+
mysql> DESC `regions`;
+-------------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+------------------+------+-----+---------+----------------+
| id | int(11) unsigned | NO | PRI | NULL | auto_increment |
| provinceid | int(11) unsigned | NO | | NULL | |
| region | varchar(300) | NO | | NULL | |
| min_zipcode | int(5) unsigned | NO | | NULL | |
| max_zipcode | int(5) unsigned | NO | | NULL | |
+-------------+------------------+------+-----+---------+----------------+
mysql> DESC `issues`;
+------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+---------------------+------+-----+---------+----------------+
| id | bigint(11) unsigned | NO | PRI | NULL | auto_increment |
| categoryid | int(11) unsigned | NO | | NULL | |
| country | varchar(150) | NO | | NULL | |
| zipcode | int(5) | NO | | NULL | |
+------------+---------------------+------+-----+---------+----------------+
mysql> DESC `experts`;
+---------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------+------------------+------+-----+---------+----------------+
| id | int(11) unsigned | NO | PRI | NULL | auto_increment |
| country | varchar(150) | NO | | none | |
+---------+------------------+------+-----+---------+----------------+
mysql> DESC `experts_categories`;
+------------+------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+------------------+------+-----+---------+-------+
| expertid | int(11) unsigned | NO | PRI | NULL | |
| categoryid | int(11) unsigned | NO | PRI | NULL | |
+------------+------------------+------+-----+---------+-------+
mysql> DESC `experts_provinces`;
+------------+------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+------------------+------+-----+---------+-------+
| expertid | int(11) unsigned | NO | PRI | NULL | |
| provinceid | int(11) unsigned | NO | PRI | NULL | |
+------------+------------------+------+-----+---------+-------+
mysql> DESC `experts_regions`;
+----------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------+---------+------+-----+---------+-------+
| expertid | int(11) | NO | PRI | NULL | |
| regionid | int(11) | NO | PRI | NULL | |
+----------+---------+------+-----+---------+-------+
4. 視覺記錄
mysql> SELECT * FROM `categories`;
+----+----------+
| id | name |
+----+----------+
| 1 | Software |
| 2 | Hardware |
+----+----------+
mysql> SELECT * FROM `provinces`;
+----+---------+----------------+-------------+-------------+
| id | country | province | min_zipcode | max_zipcode |
+----+---------+----------------+-------------+-------------+
| 1 | Germany | Province One | 1000 | 1299 |
| 2 | Germany | Province Two | 1300 | 1499 |
| 3 | Germany | Province Three | 1500 | 1999 |
| 4 | Germany | Province Four | 2000 | 2899 |
| 5 | France | Province One | 1000 | 1799 |
| 6 | France | Province Two | 1800 | 2199 |
| 7 | France | Province Three | 2200 | 2399 |
+----+---------+----------------+-------------+-------------+
mysql> SELECT * FROM `regions`;
+----+------------+--------------+-------------+-------------+
| id | provinceid | region | min_zipcode | max_zipcode |
+----+------------+--------------+-------------+-------------+
| 1 | 1 | Region One | 1000 | 1099 |
| 2 | 1 | Region Two | 1100 | 1159 |
| 3 | 1 | Region Three | 1160 | 1299 |
| 4 | 2 | Region One | 1300 | 1400 |
| 5 | 2 | Region Two | 1401 | 1499 |
| 6 | 3 | Region One | 1500 | 1699 |
| 7 | 3 | Region Two | 1700 | 1999 |
| 8 | 4 | Region One | 2000 | 2299 |
| 9 | 4 | Region Two | 2300 | 2599 |
| 10 | 4 | Region Three | 2600 | 2699 |
| 11 | 4 | Region Four | 2700 | 2899 |
| 12 | 5 | Region One | 1000 | 1699 |
| 13 | 5 | Region Two | 1700 | 1799 |
| 14 | 6 | Region One | 1800 | 2000 |
| 15 | 6 | Region Two | 2001 | 2199 |
| 16 | 7 | Region One | 2200 | 2299 |
| 17 | 7 | Region Two | 2300 | 2399 |
+----+------------+--------------+-------------+-------------+
mysql> SELECT * FROM `issues`;
+----+------------+---------+---------+
| id | categoryid | country | zipcode |
+----+------------+---------+---------+
| 1 | 2 | Germany | 2100 |
| 2 | 1 | France | 1900 |
| 3 | 1 | Germany | 1500 |
| 4 | 2 | Germany | 2800 |
| 5 | 2 | France | 1850 |
+----+------------+---------+---------+
mysql> SELECT * FROM `experts`;
+----+---------+
| id | country |
+----+---------+
| 1 | Germany |
| 2 | France |
| 3 | Germany |
+----+---------+
mysql> SELECT * FROM `experts_categories`;
+----------+------------+
| expertid | categoryid |
+----------+------------+
| 1 | 1 |
| 1 | 2 |
| 2 | 1 |
| 3 | 1 |
+----------+------------+
mysql> SELECT * FROM `experts_provinces`;
+----------+------------+
| expertid | provinceid |
+----------+------------+
| 1 | 4 |
| 2 | 6 |
| 2 | 7 |
+----------+------------+
mysql> SELECT * FROM `experts_regions`;
+----------+----------+
| expertid | regionid |
+----------+----------+
| 1 | 8 |
| 1 | 10 |
+----------+----------+
三、 解決方案
我已經設法想出了一半的解決方案。
1.我的一半解決方案
一個問題：
SELECT
`i`.`id` `issue_id`,
`e`.`id` `expert_id`
FROM `issues` `i`
INNER JOIN `experts` `e`
ON `i`.`country` = `e`.`country`
INNER JOIN `experts_categories` `ec`
ON `e`.`id` = `ec`.`expertid`
AND `i`.`categoryid` = `ec`.`categoryid`
ORDER BY `e`.`id`, `ec`.`categoryid` ASC
b) 結果：
+----------+-----------+
| issue_id | expert_id |
+----------+-----------+
| 3 | 1 |
| 1 | 1 |
| 4 | 1 |
| 2 | 2 |
| 3 | 3 |
+----------+-----------+
c) 准確的結果應該是：
+----------+-----------+
| issue_id | expert_id |
+----------+-----------+
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
+----------+-----------+
解釋一下，為什么上面的視覺結果是准確的。
首先，讓我們獲得一個“完全連接”，以便我們進行比較：
d) 查詢：
SELECT
`i`.`id` `issue_id`, `e`.`id` `expert_id`, `i`.`categoryid` `issue_category_id`, `ec`.`categoryid` `expert_category_id`,
`i`.`country` `issue_country`, `e`.`country` `expert_country`,
`i`.`zipcode` `issue_zipcode`,
`p`.`id` `province_id`, `p`.`min_zipcode` `province_min_zipcode`, `p`.`max_zipcode` `province_max_zipcode`,
`r`.`id` `region_id`, `r`.`min_zipcode` `region_min_zipcode`, `r`.`max_zipcode` `region_max_zipcode`
FROM `issues` `i`
INNER JOIN `experts` `e`
ON `i`.`country` = `e`.`country`
INNER JOIN `experts_categories` `ec`
ON `ec`.`expertid` = `e`.`id`
AND `i`.`categoryid` = `ec`.`categoryid`
LEFT JOIN `experts_provinces` `ep`
ON `e`.`id` = `ep`.`expertid`
LEFT JOIN `provinces` `p`
ON `ep`.`provinceid` = `p`.`id`
LEFT JOIN `experts_regions` `er`
ON `e`.`id` = `er`.`expertid`
LEFT JOIN `regions` `r`
ON `er`.`regionid` = `r`.`id`
AND `p`.`id` = `r`.`provinceid`
ORDER BY `e`.`id`,`ec`.`categoryid` ASC
e) 結果：
+----------+-----------+-------------------+--------------------+---------------+----------------+---------------+-------------+----------------------+----------------------+-----------+--------------------+--------------------+
| issue_id | expert_id | issue_category_id | expert_category_id | issue_country | expert_country | issue_zipcode | province_id | province_min_zipcode | province_max_zipcode | region_id | region_min_zipcode | region_max_zipcode |
+----------+-----------+-------------------+--------------------+---------------+----------------+---------------+-------------+----------------------+----------------------+-----------+--------------------+--------------------+
| 3 | 1 | 1 | 1 | Germany | Germany | 1500 | 4 | 2000 | 2899 | 10 | 2600 | 2699 |
| 3 | 1 | 1 | 1 | Germany | Germany | 1500 | 4 | 2000 | 2899 | 8 | 2000 | 2299 |
| 1 | 1 | 2 | 2 | Germany | Germany | 2100 | 4 | 2000 | 2899 | 10 | 2600 | 2699 |
| 1 | 1 | 2 | 2 | Germany | Germany | 2100 | 4 | 2000 | 2899 | 8 | 2000 | 2299 |
| 4 | 1 | 2 | 2 | Germany | Germany | 2800 | 4 | 2000 | 2899 | 10 | 2600 | 2699 |
| 4 | 1 | 2 | 2 | Germany | Germany | 2800 | 4 | 2000 | 2899 | 8 | 2000 | 2299 |
| 2 | 2 | 1 | 1 | France | France | 1900 | 7 | 2200 | 2399 | NULL | NULL | NULL |
| 2 | 2 | 1 | 1 | France | France | 1900 | 6 | 1800 | 2199 | NULL | NULL | NULL |
| 3 | 3 | 1 | 1 | Germany | Germany | 1500 | NULL | NULL | NULL | NULL | NULL | NULL |
+----------+-----------+-------------------+--------------------+---------------+----------------+---------------+-------------+----------------------+----------------------+-----------+--------------------+--------------------+
所以比較（b）查詢結果和（c），手動修復結果，我們可以注意到......
-
issue_id編號3不能分配給expert_id編號1，因為issue_id編號1來自國家Germany，就像專家一樣，被分配在category_id編號2上，就像專家一樣，但有一個expert_id代碼1500和專家編號1被分配僅從該province_id的provinceID 號4和regions_id號8和10處理issues。 所以regionszip 代碼范圍從2000到2299和從2600到2699，我們的issuezip 代碼不屬於這些區域。 -
issue_idnumber1可以分配給expert_idnumber1，因為issue_idnumber1來自國家Germany，就像專家一樣，被分配在category_id編號2上，就像專家一樣，有一個 zip 代碼2100，它在邊界之間省內的province_id4號和region_id8號，分配給expert_id1號覆蓋。 -
issue_idnumber4不能分配給expert_idnumber1，因為issue_idnumber4來自國家Germany，就像專家一樣，被分配在category_idnumber4上，但是有一個 zip 代碼2800，它在province_id編號的邊界內4，但不在region_id編號8和10的邊界內，它被分配為由expert_id編號1覆蓋 -
issue_idnumber2可以分配給expert_idnumber2，因為issue_idnumber2來自國家France，就像專家一樣，被分配在category_id編號1上，就像專家一樣，有一個 zip 代碼1900，在邊界內province_id編號6，分配給該專家。 -
issue_idnumber3可以分配給expert_idnumber3，因為issue_idnumber3來自國家Germany，就像專家一樣，被分配在category_id編號1上，就像專家一樣。 而且，這位專家沒有任何行政區划限制。 也就是說，這位專家可以issues所有Germany的問題
因此，我們列出了所有可以分配給experts的issues 。
2. 缺半解
如您所見，我的半解決方案沒有考慮行政區划限制。
我不能使用過程或視圖來實現這一點，但是，如果有幫助的話，我可以將其拆分為多個查詢。
數據庫為 MySQL (5.0.1 - MySQL 社區服務器 (GPL))，編程語言為 PHP (5.1)。
2 個解決方案
解決方案1
3 已采納 2011-06-12 14:14:41
我只是修改了@krubo 的答案。
如果你想要子查詢，查詢將是：
SELECT
tis.id AS issue_id,
tex.id AS expert_id,
tis.categoryid AS issue_category_id,
tex.categoryid AS expert_category_id,
tis.country AS issue_country,
tex.country AS expert_country,
tis.zipcode AS issue_zipcode,
tis.provinceid AS province_id,
tis.province_minzipcode AS province_minzipcode,
tis.province_maxzipcode AS province_maxzipcode,
tis.regionid AS region_id,
tis.region_minzipcode AS region_minzipcode,
tis.region_maxzipcode AS region_maxzipcode
FROM
(
SELECT
i.id, categoryid, i.country, zipcode,
provinces.id AS provinceid, provinces.min_zipcode AS province_minzipcode,
provinces.max_zipcode AS province_maxzipcode, regions.id AS regionid,
regions.min_zipcode AS region_minzipcode,
regions.max_zipcode AS region_maxzipcode
FROM
issues AS i
LEFT JOIN provinces ON i.country=provinces.country
AND i.zipcode BETWEEN provinces.min_zipcode AND provinces.max_zipcode
LEFT JOIN regions on provinces.id=regions.provinceid
AND i.zipcode BETWEEN regions.min_zipcode AND regions.max_zipcode
) AS tis
JOIN
(
SELECT
e.id, country, categoryid, provinceid, regionid
FROM
experts e
JOIN experts_categories ON e.id=experts_categories.expertid
LEFT JOIN experts_provinces ON e.id=experts_provinces.expertid
LEFT JOIN experts_regions ON e.id=experts_regions.expertid
) AS tex
WHERE
tis.country=tex.country
AND tis.categoryid=tex.categoryid
AND (tis.provinceid IS NULL
OR tex.provinceid IS NULL
OR tis.provinceid=tex.provinceid)
AND (tis.regionid IS NULL
OR tex.regionid IS NULL
OR tis.regionid=tex.regionid);
結果是：
+----------+-----------+-------------------+--------------------+---------------+----------------+---------------+-------------+----------------------+----------------------+-----------+--------------------+--------------------+
| issue_id | expert_id | issue_category_id | expert_category_id | issue_country | expert_country | issue_zipcode | province_id | province_min_zipcode | province_max_zipcode | region_id | region_min_zipcode | region_max_zipcode |
+----------+-----------+-------------------+--------------------+---------------+----------------+---------------+-------------+----------------------+----------------------+-----------+--------------------+--------------------+
| 1 | 1 | 2 | 2 | Germany | Germany | 2100 | 4 | 2000 | 2899 | 8 | 2000 | 2299 |
| 2 | 2 | 1 | 1 | France | France | 1900 | 6 | 2000 | 2199 | 14 | 1800 | 2000 |
| 3 | 3 | 1 | 1 | Germany | Germany | 1500 | 3 | 2000 | 1999 | 6 | 1500 | 1699 |
解決方案2
2 2011-06-11 18:16:54
如果您不使用至少一個視圖來組織它，您的 SQL 將非常復雜。 嘗試使用此視圖將每個問題與省和地區匹配：
create view viewissues as
select issues.id, categoryid, issues.country, zipcode,
provinces.id as provinceid, regions.id as regionid
from issues
left join provinces on issues.country=provinces.country
and issues.zipcode between provinces.min_zipcode and provinces.max_zipcode
left join regions on provinces.id=regions.provinceid
and issues.zipcode between regions.min_zipcode and regions.max_zipcode;
此視圖根據專家的類別、省份（如果有）和地區（如果有）列出專家：
create view viewexperts as
select experts.id, country, categoryid, provinceid, regionid
from experts
join experts_categories on experts.id=experts_categories.expertid
left join experts_provinces on experts.id=experts_provinces.expertid
left join experts_regions on experts.id=experts_regions.expertid;
現在，通過基於這些視圖進行選擇，您的最終查詢可以更易於管理：
select distinct viewissues.id, viewexperts.id
from viewissues join viewexperts
where viewissues.country=viewexperts.country
and viewissues.categoryid=viewexperts.categoryid
and (viewissues.provinceid is null
or viewexperts.provinceid is null
or viewissues.provinceid=viewexperts.provinceid)
and (viewissues.regionid is null
or viewexperts.regionid is null
or viewissues.regionid=viewexperts.regionid);
MySQL表中的多個連接
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