MySQL基础五：子查询与链接_MySQL
本篇文章参考：http://www.imooc.com/learn/122
首先下载好数据，网址上面有；
#首先录入数据：
CREATE TABLE IF NOT EXISTS tdb_goods(
goods_id SMALLINT UNSIGNED PRIMARY KEY AUTO_INCREMENT,
goods_name VARCHAR(150) NOT NULL,
goods_cate VARCHAR(40) NOT NULL,
brand_name VARCHAR(40) NOT NULL,
goods_price DECIMAL(15,3) UNSIGNED NOT NULL DEFAULT 0,
is_show BOOLEAN NOT NULL DEFAULT 1,
is_saleoff BOOLEAN NOT NULL DEFAULT 0
);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('R510VC 15.6英寸笔记本','笔记本','华硕','3399',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('Y400N 14.0英寸笔记本电脑','笔记本','联想','4899',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('G150TH 15.6英寸游戏本','游戏本','雷神','8499',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('X550CC 15.6英寸笔记本','笔记本','华硕','2799',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('X240(20ALA0EYCD) 12.5英寸超极本','超级本','联想','4999',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('U330P 13.3英寸超极本','超级本','联想','4299',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('SVP13226SCB 13.3英寸触控超极本','超级本','索尼','7999',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('iPad mini MD531CH/A 7.9英寸平板电脑','平板电脑','苹果','1998',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版）','平板电脑','苹果','3388',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES(' iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑
（16G WiFi版）','平板电脑','苹果','2788',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('IdeaCentre C340 20英寸一体电脑 ','台式机','联想','3499',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('Vostro 3800-R1206 台式电脑','台式机','戴尔','2899',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('iMac ME086CH/A 21.5英寸一体电脑','台式机','苹果','9188',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ）','
台式机','宏碁','3699',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('Z220SFF F4F06PA工作站','服务器/工作站','惠普','4288',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('PowerEdge T110 II服务器','服务器/工作站','戴尔','5388',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('Mac Pro MD878CH/A 专业级台式电脑','服务器/工作站','苹果','28888',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES(' HMZ-T3W 头戴显示设备','笔记本配件','索尼','6999',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('商务双肩背包','笔记本配件','索尼','99',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('X3250 M4机架式服务器 2583i14','服务器/工作站','IBM','6888',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('玄龙精英版 笔记本散热器','笔记本配件','九州风神','',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES(' HMZ-T3W 头戴显示设备','笔记本配件','索尼','6999',DEFAULT,DEFAULT);
INSERT tdb_goods (goods_name,goods_cate,brand_name,goods_price,is_show,is_saleoff)
VALUES('商务双肩背包','笔记本配件','索尼','99',DEFAULT,DEFAULT);
#查看数据表；
mysql>
mysql> SHOW TABLES;
+-----------------+
| Tables_in_world |
+-----------------+
| city |
| country |
| countrylanguage |
| provinces |
| tdb_goods |
| test |
| users |
+-----------------+
7 rows in set (0.00 sec)
mysql> SHOW COLUMNS FROM tdb_goods;
+-------------+------------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+------------------------+------+-----+---------+----------------+
| goods_id | smallint(5) unsigned | NO | PRI | NULL | auto_increment |
| goods_name | varchar(150) | NO | | NULL | |
| goods_cate | varchar(40) | NO | | NULL | |
| brand_name | varchar(40) | NO | | NULL | |
| goods_price | decimal(15,3) unsigned | NO | | 0.000 | |
| is_show | tinyint(1) | NO | | 1 | |
| is_saleoff | tinyint(1) | NO | | 0 | |
+-------------+------------------------+------+-----+---------+----------------+
7 rows in set (0.01 sec)
mysql> SELECT * FROM tdb_goods\G;
*************************** 1. row ***************************
goods_id: 1
goods_name: R510VC 15.6英寸笔记本
goods_cate: 笔记本
brand_name: 华硕
goods_price: 3399.000
is_show: 1
is_saleoff: 0
*************************** 2. row ***************************
goods_id: 2
goods_name: Y400N 14.0英寸笔记本电脑
goods_cate: 笔记本
brand_name: 联想
goods_price: 4899.000
is_show: 1
is_saleoff: 0
*************************** 3. row ***************************
goods_id: 3
goods_name: G150TH 15.6英寸游戏本
goods_cate: 游戏本
brand_name: 雷神
goods_price: 8499.000
is_show: 1
is_saleoff: 0
*************************** 4. row ***************************
goods_id: 4
goods_name: X550CC 15.6英寸笔记本
goods_cate: 笔记本
brand_name: 华硕
goods_price: 2799.000
is_show: 1
is_saleoff: 0
*************************** 5. row ***************************
goods_id: 5
goods_name: X240(20ALA0EYCD) 12.5英寸超极本
goods_cate: 超级本
brand_name: 联想
goods_price: 4999.000
is_show: 1
is_saleoff: 0
*************************** 6. row ***************************
goods_id: 6
goods_name: U330P 13.3英寸超极本
goods_cate: 超级本
brand_name: 联想
goods_price: 4299.000
is_show: 1
is_saleoff: 0
*************************** 7. row ***************************
goods_id: 7
goods_name: SVP13226SCB 13.3英寸触控超极本
goods_cate: 超级本
brand_name: 索尼
goods_price: 7999.000
is_show: 1
is_saleoff: 0
*************************** 8. row ***************************
goods_id: 8
goods_name: iPad mini MD531CH/A 7.9英寸平板电脑
goods_cate: 平板电脑
brand_name: 苹果
goods_price: 1998.000
is_show: 1
is_saleoff: 0
*************************** 9. row ***************************
goods_id: 9
goods_name: iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版）
goods_cate: 平板电脑
brand_name: 苹果
goods_price: 3388.000
is_show: 1
is_saleoff: 0
*************************** 10. row ***************************
goods_id: 10
goods_name: iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版）
goods_cate: 平板电脑
brand_name: 苹果
goods_price: 2788.000
is_show: 1
is_saleoff: 0
*************************** 11. row ***************************
goods_id: 11
goods_name: IdeaCentre C340 20英寸一体电脑
goods_cate: 台式机
brand_name: 联想
goods_price: 3499.000
is_show: 1
is_saleoff: 0
*************************** 12. row ***************************
goods_id: 12
goods_name: Vostro 3800-R1206 台式电脑
goods_cate: 台式机
brand_name: 戴尔
goods_price: 2899.000
is_show: 1
is_saleoff: 0
*************************** 13. row ***************************
goods_id: 13
goods_name: iMac ME086CH/A 21.5英寸一体电脑
goods_cate: 台式机
brand_name: 苹果
goods_price: 9188.000
is_show: 1
is_saleoff: 0
*************************** 14. row ***************************
goods_id: 14
goods_name: AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ）
goods_cate: 台式机
brand_name: 宏碁
goods_price: 3699.000
is_show: 1
is_saleoff: 0
*************************** 15. row ***************************
goods_id: 15
goods_name: Z220SFF F4F06PA工作站
goods_cate: 服务器/工作站
brand_name: 惠普
goods_price: 4288.000
is_show: 1
is_saleoff: 0
*************************** 16. row ***************************
goods_id: 16
goods_name: PowerEdge T110 II服务器
goods_cate: 服务器/工作站
brand_name: 戴尔
goods_price: 5388.000
is_show: 1
is_saleoff: 0
*************************** 17. row ***************************
goods_id: 17
goods_name: Mac Pro MD878CH/A 专业级台式电脑
goods_cate: 服务器/工作站
brand_name: 苹果
goods_price: 28888.000
is_show: 1
is_saleoff: 0
*************************** 18. row ***************************
goods_id: 18
goods_name: HMZ-T3W 头戴显示设备
goods_cate: 笔记本配件
brand_name: 索尼
goods_price: 6999.000
is_show: 1
is_saleoff: 0
*************************** 19. row ***************************
goods_id: 19
goods_name: 商务双肩背包
goods_cate: 笔记本配件
brand_name: 索尼
goods_price: 99.000
is_show: 1
is_saleoff: 0
*************************** 20. row ***************************
goods_id: 20
goods_name: X3250 M4机架式服务器 2583i14
goods_cate: 服务器/工作站
brand_name: IBM
goods_price: 6888.000
is_show: 1
is_saleoff: 0
*************************** 21. row ***************************
goods_id: 21
goods_name: HMZ-T3W 头戴显示设备
goods_cate: 笔记本配件
brand_name: 索尼
goods_price: 6999.000
is_show: 1
is_saleoff: 0
*************************** 22. row ***************************
goods_id: 22
goods_name: 商务双肩背包
goods_cate: 笔记本配件
brand_name: 索尼
goods_price: 99.000
is_show: 1
is_saleoff: 0
22 rows in set (0.01 sec)
ERROR:
No query specifiedCopy after login
子查询正文
mysql> #子查询
mysql> #子查询是嵌套在查询内部的查询；
mysql>
mysql> #使用比较运算符的子查询；
mysql> #求价格平均值；
mysql> SELECT AVG(goods_price) FROM tdb_goods;
mysql> SELECT AVG(goods_price) FROM tdb_goods;
+------------------+
| AVG(goods_price) |
+------------------+
| 5636.3636364 |
+------------------+
1 row in set (0.03 sec)
mysql> #四舍五入
mysql> #保留到小数点后两位； mysql> SELECT ROUND(AVG(goods_price),2) FROM tdb_goods;
+---------------------------+
| ROUND(AVG(goods_price),2) |
+---------------------------+
| 5636.36 |
+---------------------------+
1 row in set (0.02 sec)
mysql> SELECT goods_id,goods_price FROM tdb_goods WHERE goods_price>=5636.36;
+----------+-------------+
| goods_id | goods_price |
+----------+-------------+
| 3 | 8499.000 |
| 7 | 7999.000 |
| 13 | 9188.000 |
| 17 | 28888.000 |
| 18 | 6999.000 |
| 20 | 6888.000 |
| 21 | 6999.000 |
+----------+-------------+
7 rows in set (0.00 sec)
mysql> #通过子查询实现上式；
mysql> SELECT goods_id,goods_price FROM tdb_goods WHERE goods_price>=(SELECT ROUND(AVG(goods_price),2)
FROM tdb_goods);
+----------+-------------+
| goods_id | goods_price |
+----------+-------------+
| 3 | 8499.000 |
| 7 | 7999.000 |
| 13 | 9188.000 |
| 17 | 28888.000 |
| 18 | 6999.000 |
| 20 | 6888.000 |
| 21 | 6999.000 |
+----------+-------------+
7 rows in set (0.03 sec)
mysql> SELECT goods_price FROM tdb_goods WHERE goods_cate='超级本';
+-------------+
| goods_price |
+-------------+
| 4999.000 |
| 4299.000 |
| 7999.000 |
+-------------+
3 rows in set (0.00 sec)
mysql> SELECT * FROM tdb_goods WHERE goods_cate='超级本'\G;
*************************** 1. row ***************************
goods_id: 5
goods_name: X240(20ALA0EYCD) 12.5英寸超极本
goods_cate: 超级本
brand_name: 联想
goods_price: 4999.000
is_show: 1
is_saleoff: 0
*************************** 2. row ***************************
goods_id: 6
goods_name: U330P 13.3英寸超极本
goods_cate: 超级本
brand_name: 联想
goods_price: 4299.000
is_show: 1
is_saleoff: 0
*************************** 3. row ***************************
goods_id: 7
goods_name: SVP13226SCB 13.3英寸触控超极本
goods_cate: 超级本
brand_name: 索尼
goods_price: 7999.000
is_show: 1
is_saleoff: 0
3 rows in set (0.00 sec)
ERROR:
No query specified
mysql> SELECT goods_id,goods_name,goods_price FROM tdb_goods WHERE goods_price>
(SELECT goods_price FROM tdb_goods WHERE goods_cate='超级本');
ERROR 1242 (21000): Subquery returns more than 1 row
mysql> #鉴于上述错误，子查询用三个关键字修饰
mysql> SELECT goods_id,goods_name,goods_price FROM tdb_goods WHERE goods_price>ANY
(SELECT goods_price FROM tdb_goods WHERE goods_cate='超级本');
+----------+----------------------------------+-------------+
| goods_id | goods_name | goods_price |
+----------+----------------------------------+-------------+
| 2 | Y400N 14.0英寸笔记本电脑 | 4899.000 |
| 3 | G150TH 15.6英寸游戏本 | 8499.000 |
| 5 | X240(20ALA0EYCD) 12.5英寸超极本 | 4999.000 |
| 7 | SVP13226SCB 13.3英寸触控超极本 | 7999.000 |
| 13 | iMac ME086CH/A 21.5英寸一体电脑 | 9188.000 |
| 16 | PowerEdge T110 II服务器 | 5388.000 |
| 17 | Mac Pro MD878CH/A 专业级台式电脑 | 28888.000 |
| 18 | HMZ-T3W 头戴显示设备 | 6999.000 |
| 20 | X3250 M4机架式服务器 2583i14 | 6888.000 |
| 21 | HMZ-T3W 头戴显示设备 | 6999.000 |
+----------+----------------------------------+-------------+
10 rows in set (0.00 sec)
mysql> SELECT goods_id,goods_name,goods_price FROM tdb_goods WHERE goods_price>ALL
(SELECT goods_price FROM tdb_goods WHERE goodscate='超级本');
+----------+----------------------------------+-------------+
| goods_id | goods_name | goods_price |
+----------+----------------------------------+-------------+
| 3 | G150TH 15.6英寸游戏本 | 8499.000 |
| 13 | iMac ME086CH/A 21.5英寸一体电脑 | 9188.000 |
| 17 | Mac Pro MD878CH/A 专业级台式 脑 | 28888.000 |
+----------+----------------------------------+-------------+
3 rows in set (0.01 sec)
mysql> #使用 in 和not in 引发的子查询；
mysql> #EXIST 和not EXIST 引发的子查询
mysql> #创建商品标签数据表：
mysql> CREATE TABLE IF NOT EXISTS tdb_goods_cate(
-> cate_id SMALLINT UNSIGNED PRIMARY KEY AUTO_INCREMENT,
-> cate_name VARCHAR(40) NOT NULL
-> );
Query OK, 0 rows affected (0.18 sec)
mysql> #得到商品分类；
mysql> SELECT goods_cate FROM tdb_goods GROUP BY goods_cate;
+---------------+
| goods_cate |
+---------------+
| 台式机 |
| 平板电脑 |
| 服务器/工作站 |
| 游戏本 |
| 笔记本 |
| 笔记本配件 |
| 超级本 |
+---------------+
7 rows in set (0.00 sec)
mysql> #将查询的结果写入的数据表中、
mysql> SELECT * FROM tdb_goods_cate;
Empty set (0.00 sec)
mysql> DESC tdb_goods_cate;
+-----------+----------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+----------------------+------+-----+---------+----------------+
| cate_id | smallint(5) unsigned | NO | PRI | NULL | auto_increment |
| cate_name | varchar(40) | NO | | NULL | |
+-----------+----------------------+------+-----+---------+----------------+
2 rows in set (0.01 sec)
mysql> INSERT tdb_goods_cate(cate_name) SELECT goods_cate FROM tdb_goods GROUP BY goods_cate;
Query OK, 7 rows affected (0.04 sec)
Records: 7 Duplicates: 0 Warnings: 0
mysql> SELECT * FROM tdb_goods_cate;
+---------+---------------+
| cate_id | cate_name |
+---------+---------------+
| 1 | 台式机 |
| 2 | 平板电脑 |
| 3 | 服务器/工作站 |
| 4 | 游戏本 |
| 5 | 笔记本 |
| 6 | 笔记本配件 |
| 7 | 超级本 |
+---------+---------------+
7 rows in set (0.00 sec)
mysql> #参照分类表更新商品表、
mysql> UPDATE tdb_goods INNER JOIN tdb_goods_cate ON goods_cate=cate_name SET goods_cate=cate_id;
Query OK, 22 rows affected (0.21 sec)
Rows matched: 22 Changed: 22 Warnings: 0
mysql> SELECT * FROM tdb_goods\G;
*************************** 1. row ***************************
goods_id: 1
goods_name: R510VC 15.6英寸笔记本
goods_cate: 5
brand_name: 华硕
goods_price: 3399.000
is_show: 1
is_saleoff: 0
*************************** 2. row ***************************
goods_id: 2
goods_name: Y400N 14.0英寸笔记本电脑
goods_cate: 5
brand_name: 联想
goods_price: 4899.000
is_show: 1
is_saleoff: 0
*************************** 3. row ***************************
goods_id: 3
goods_name: G150TH 15.6英寸游戏本
goods_cate: 4
brand_name: 雷神
goods_price: 8499.000
is_show: 1
is_saleoff: 0
*************************** 4. row ***************************
goods_id: 4
goods_name: X550CC 15.6英寸笔记本
goods_cate: 5
brand_name: 华硕
goods_price: 2799.000
is_show: 1
is_saleoff: 0
*************************** 5. row ***************************
goods_id: 5
goods_name: X240(20ALA0EYCD) 12.5英寸超极本
goods_cate: 7
brand_name: 联想
goods_price: 4999.000
is_show: 1
is_saleoff: 0
*************************** 6. row ***************************
goods_id: 6
goods_name: U330P 13.3英寸超极本
goods_cate: 7
brand_name: 联想
goods_price: 4299.000
is_show: 1
is_saleoff: 0
*************************** 7. row ***************************
goods_id: 7
goods_name: SVP13226SCB 13.3英寸触控超极本
goods_cate: 7
brand_name: 索尼
goods_price: 7999.000
is_show: 1
is_saleoff: 0
*************************** 8. row ***************************
goods_id: 8
goods_name: iPad mini MD531CH/A 7.9英寸平板电脑
goods_cate: 2
brand_name: 苹果
goods_price: 1998.000
is_show: 1
is_saleoff: 0
*************************** 9. row ***************************
goods_id: 9
goods_name: iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版）
goods_cate: 2
brand_name: 苹果
goods_price: 3388.000
is_show: 1
is_saleoff: 0
*************************** 10. row ***************************
goods_id: 10
goods_name: iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版）
goods_cate: 2
brand_name: 苹果
goods_price: 2788.000
is_show: 1
is_saleoff: 0
*************************** 11. row ***************************
goods_id: 11
goods_name: IdeaCentre C340 20英寸一体电脑
goods_cate: 1
brand_name: 联想
goods_price: 3499.000
is_show: 1
is_saleoff: 0
*************************** 12. row ***************************
goods_id: 12
goods_name: Vostro 3800-R1206 台式电脑
goods_cate: 1
brand_name: 戴尔
goods_price: 2899.000
is_show: 1
is_saleoff: 0
*************************** 13. row ***************************
goods_id: 13
goods_name: iMac ME086CH/A 21.5英寸一体电脑
goods_cate: 1
brand_name: 苹果
goods_price: 9188.000
is_show: 1
is_saleoff: 0
*************************** 14. row ***************************
goods_id: 14
goods_name: AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ）
goods_cate: 1
brand_name: 宏碁
goods_price: 3699.000
is_show: 1
is_saleoff: 0
*************************** 15. row ***************************
goods_id: 15
goods_name: Z220SFF F4F06PA工作站
goods_cate: 3
brand_name: 惠普
goods_price: 4288.000
is_show: 1
is_saleoff: 0
*************************** 16. row ***************************
goods_id: 16
goods_name: PowerEdge T110 II服务器
goods_cate: 3
brand_name: 戴尔
goods_price: 5388.000
is_show: 1
is_saleoff: 0
*************************** 17. row ***************************
goods_id: 17
goods_name: Mac Pro MD878CH/A 专业级台式电脑
goods_cate: 3
brand_name: 苹果
goods_price: 28888.000
is_show: 1
is_saleoff: 0
*************************** 18. row ***************************
goods_id: 18
goods_name: HMZ-T3W 头戴显示设备
goods_cate: 6
brand_name: 索尼
goods_price: 6999.000
is_show: 1
is_saleoff: 0
*************************** 19. row ***************************
goods_id: 19
goods_name: 商务双肩背包
goods_cate: 6
brand_name: 索尼
goods_price: 99.000
is_show: 1
is_saleoff: 0
*************************** 20. row ***************************
goods_id: 20
goods_name: X3250 M4机架式服务器 2583i14
goods_cate: 3
brand_name: IBM
goods_price: 6888.000
is_show: 1
is_saleoff: 0
*************************** 21. row ***************************
goods_id: 21
goods_name: HMZ-T3W 头戴显示设备
goods_cate: 6
brand_name: 索尼
goods_price: 6999.000
is_show: 1
is_saleoff: 0
*************************** 22. row ***************************
goods_id: 22
goods_name: 商务双肩背包
goods_cate: 6
brand_name: 索尼
goods_price: 99.000
is_show: 1
is_saleoff: 0
22 rows in set (0.00 sec)
ERROR:
No query specified
mysql> SELECT * FROM tdb_goods_brands;
+----------+------------+
| brand_id | brand_name |
+----------+------------+
| 1 | IBM |
| 2 | 华硕 |
| 3 | 宏碁 |
| 4 | 惠普 |
| 5 | 戴尔 |
| 6 | 索尼 |
| 7 | 联想 |
| 8 | 苹果 |
| 9 | 雷神 |
+----------+------------+
9 rows in set (0.00 sec)
mysql> SHOW COLUMNS FROM tdb_goods;
+-------------+------------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+------------------------+------+-----+---------+----------------+
| goods_id | smallint(5) unsigned | NO | PRI | NULL | auto_increment |
| goods_name | varchar(150) | NO | | NULL | |
| goods_cate | varchar(40) | NO | | NULL | |
| brand_name | varchar(40) | NO | | NULL | |
| goods_price | decimal(15,3) unsigned | NO | | 0.000 | |
| is_show | tinyint(1) | NO | | 1 | |
| is_saleoff | tinyint(1) | NO | | 0 | |
+-------------+------------------------+------+-----+---------+----------------+
7 rows in set (0.03 sec)
mysql> SHOW COLUMNS FROM tdb_goods_brands;
+------------+----------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+----------------------+------+-----+---------+----------------+
| brand_id | smallint(5) unsigned | NO | PRI | NULL | auto_increment |
| brand_name | varchar(40) | NO | | NULL | |
+------------+----------------------+------+-----+---------+----------------+
2 rows in set (0.00 sec)
mysql> UPDATE tdb_goods AS g INNER JOIN tdb_goods_brands AS b ON g.brand_name=b.brand_name
-> SET g.brand_name=b.brand_id;
Query OK, 22 rows affected (0.06 sec)
Rows matched: 22 Changed: 22 Warnings: 0
mysql> SELECT * FROM tdb_goods\G;
*************************** 1. row ***************************
goods_id: 1
goods_name: R510VC 15.6英寸笔记本
goods_cate: 5
brand_name: 2
goods_price: 3399.000
is_show: 1
is_saleoff: 0
*************************** 2. row ***************************
goods_id: 2
goods_name: Y400N 14.0英寸笔记本电脑
goods_cate: 5
brand_name: 7
goods_price: 4899.000
is_show: 1
is_saleoff: 0
*************************** 3. row ***************************
goods_id: 3
goods_name: G150TH 15.6英寸游戏本
goods_cate: 4
brand_name: 9
goods_price: 8499.000
is_show: 1
is_saleoff: 0
*************************** 4. row ***************************
goods_id: 4
goods_name: X550CC 15.6英寸笔记本
goods_cate: 5
brand_name: 2
goods_price: 2799.000
is_show: 1
is_saleoff: 0
*************************** 5. row ***************************
goods_id: 5
goods_name: X240(20ALA0EYCD) 12.5英寸超极本
goods_cate: 7
brand_name: 7
goods_price: 4999.000
is_show: 1
is_saleoff: 0
*************************** 6. row ***************************
goods_id: 6
goods_name: U330P 13.3英寸超极本
goods_cate: 7
brand_name: 7
goods_price: 4299.000
is_show: 1
is_saleoff: 0
*************************** 7. row ***************************
goods_id: 7
goods_name: SVP13226SCB 13.3英寸触控超极本
goods_cate: 7
brand_name: 6
goods_price: 7999.000
is_show: 1
is_saleoff: 0
*************************** 8. row ***************************
goods_id: 8
goods_name: iPad mini MD531CH/A 7.9英寸平板电脑
goods_cate: 2
brand_name: 8
goods_price: 1998.000
is_show: 1
is_saleoff: 0
*************************** 9. row ***************************
goods_id: 9
goods_name: iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版）
goods_cate: 2
brand_name: 8
goods_price: 3388.000
is_show: 1
is_saleoff: 0
*************************** 10. row ***************************
goods_id: 10
goods_name: iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版）
goods_cate: 2
brand_name: 8
goods_price: 2788.000
is_show: 1
is_saleoff: 0
*************************** 11. row ***************************
goods_id: 11
goods_name: IdeaCentre C340 20英寸一体电脑
goods_cate: 1
brand_name: 7
goods_price: 3499.000
is_show: 1
is_saleoff: 0
*************************** 12. row ***************************
goods_id: 12
goods_name: Vostro 3800-R1206 台式电脑
goods_cate: 1
brand_name: 5
goods_price: 2899.000
is_show: 1
is_saleoff: 0
*************************** 13. row ***************************
goods_id: 13
goods_name: iMac ME086CH/A 21.5英寸一体电脑
goods_cate: 1
brand_name: 8
goods_price: 9188.000
is_show: 1
is_saleoff: 0
*************************** 14. row ***************************
goods_id: 14
goods_name: AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ）
goods_cate: 1
brand_name: 3
goods_price: 3699.000
is_show: 1
is_saleoff: 0
*************************** 15. row ***************************
goods_id: 15
goods_name: Z220SFF F4F06PA工作站
goods_cate: 3
brand_name: 4
goods_price: 4288.000
is_show: 1
is_saleoff: 0
*************************** 16. row ***************************
goods_id: 16
goods_name: PowerEdge T110 II服务器
goods_cate: 3
brand_name: 5
goods_price: 5388.000
is_show: 1
is_saleoff: 0
*************************** 17. row ***************************
goods_id: 17
goods_name: Mac Pro MD878CH/A 专业级台式电脑
goods_cate: 3
brand_name: 8
goods_price: 28888.000
is_show: 1
is_saleoff: 0
*************************** 18. row ***************************
goods_id: 18
goods_name: HMZ-T3W 头戴显示设备
goods_cate: 6
brand_name: 6
goods_price: 6999.000
is_show: 1
is_saleoff: 0
*************************** 19. row ***************************
goods_id: 19
goods_name: 商务双肩背包
goods_cate: 6
brand_name: 6
goods_price: 99.000
is_show: 1
is_saleoff: 0
*************************** 20. row ***************************
goods_id: 20
goods_name: X3250 M4机架式服务器 2583i14
goods_cate: 3
brand_name: 1
goods_price: 6888.000
is_show: 1
is_saleoff: 0
*************************** 21. row ***************************
goods_id: 21
goods_name: HMZ-T3W 头戴显示设备
goods_cate: 6
brand_name: 6
goods_price: 6999.000
is_show: 1
is_saleoff: 0
*************************** 22. row ***************************
goods_id: 22
goods_name: 商务双肩背包
goods_cate: 6
brand_name: 6
goods_price: 99.000
is_show: 1
is_saleoff: 0
22 rows in set (0.00 sec)
ERROR:
No query specified
mysql> SHOW COLUMNS FROM tdb_goods;
+-------------+------------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+------------------------+------+-----+---------+----------------+
| goods_id | smallint(5) unsigned | NO | PRI | NULL | auto_increment |
| goods_name | varchar(150) | NO | | NULL | |
| goods_cate | varchar(40) | NO | | NULL | |
| brand_name | varchar(40) | NO | | NULL | |
| goods_price | decimal(15,3) unsigned | NO | | 0.000 | |
| is_show | tinyint(1) | NO | | 1 | |
| is_saleoff | tinyint(1) | NO | | 0 | |
+-------------+------------------------+------+-----+---------+----------------+
7 rows in set (0.00 sec)
mysql> ALTER TABLE tdb_goods
-> CHANGE goods_cate cate_id SMALLINT UNSIGNED NOT NULL,
-> CHANGE brand_name brand_id SMALLINT UNSIGNED NOT NULL;
Query OK, 22 rows affected (0.67 sec)
Records: 22 Duplicates: 0 Warnings: 0
mysql> SHOW COLUMNS FROM tdb_goods;
+-------------+------------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+------------------------+------+-----+---------+----------------+
| goods_id | smallint(5) unsigned | NO | PRI | NULL | auto_increment |
| goods_name | varchar(150) | NO | | NULL | |
| cate_id | smallint(5) unsigned | NO | | NULL | |
| brand_id | smallint(5) unsigned | NO | | NULL | |
| goods_price | decimal(15,3) unsigned | NO | | 0.000 | |
| is_show | tinyint(1) | NO | | 1 | |
| is_saleoff | tinyint(1) | NO | | 0 | |
+-------------+------------------------+------+-----+---------+----------------+
7 rows in set (0.00 sec)
mysql> #创建一个事实的外键；
mysql> SELECT * FROM tdb_goods\G;
*************************** 1. row ***************************
goods_id: 1
goods_name: R510VC 15.6英寸笔记本
cate_id: 5
brand_id: 2
goods_price: 3399.000
is_show: 1
is_saleoff: 0
*************************** 2. row ***************************
goods_id: 2
goods_name: Y400N 14.0英寸笔记本电脑
cate_id: 5
brand_id: 7
goods_price: 4899.000
is_show: 1
is_saleoff: 0
*************************** 3. row ***************************
goods_id: 3
goods_name: G150TH 15.6英寸游戏本
cate_id: 4
brand_id: 9
goods_price: 8499.000
is_show: 1
is_saleoff: 0
*************************** 4. row ***************************
goods_id: 4
goods_name: X550CC 15.6英寸笔记本
cate_id: 5
brand_id: 2
goods_price: 2799.000
is_show: 1
is_saleoff: 0
*************************** 5. row ***************************
goods_id: 5
goods_name: X240(20ALA0EYCD) 12.5英寸超极本
cate_id: 7
brand_id: 7
goods_price: 4999.000
is_show: 1
is_saleoff: 0
*************************** 6. row ***************************
goods_id: 6
goods_name: U330P 13.3英寸超极本
cate_id: 7
brand_id: 7
goods_price: 4299.000
is_show: 1
is_saleoff: 0
*************************** 7. row ***************************
goods_id: 7
goods_name: SVP13226SCB 13.3英寸触控超极本
cate_id: 7
brand_id: 6
goods_price: 7999.000
is_show: 1
is_saleoff: 0
*************************** 8. row ***************************
goods_id: 8
goods_name: iPad mini MD531CH/A 7.9英寸平板电脑
cate_id: 2
brand_id: 8
goods_price: 1998.000
is_show: 1
is_saleoff: 0
*************************** 9. row ***************************
goods_id: 9
goods_name: iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版）
cate_id: 2
brand_id: 8
goods_price: 3388.000
is_show: 1
is_saleoff: 0
*************************** 10. row ***************************
goods_id: 10
goods_name: iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版）
cate_id: 2
brand_id: 8
goods_price: 2788.000
is_show: 1
is_saleoff: 0
*************************** 11. row ***************************
goods_id: 11
goods_name: IdeaCentre C340 20英寸一体电脑
cate_id: 1
brand_id: 7
goods_price: 3499.000
is_show: 1
is_saleoff: 0
*************************** 12. row ***************************
goods_id: 12
goods_name: Vostro 3800-R1206 台式电脑
cate_id: 1
brand_id: 5
goods_price: 2899.000
is_show: 1
is_saleoff: 0
*************************** 13. row ***************************
goods_id: 13
goods_name: iMac ME086CH/A 21.5英寸一体电脑
cate_id: 1
brand_id: 8
goods_price: 9188.000
is_show: 1
is_saleoff: 0
*************************** 14. row ***************************
goods_id: 14
goods_name: AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ）
cate_id: 1
brand_id: 3
goods_price: 3699.000
is_show: 1
is_saleoff: 0
*************************** 15. row ***************************
goods_id: 15
goods_name: Z220SFF F4F06PA工作站
cate_id: 3
brand_id: 4
goods_price: 4288.000
is_show: 1
is_saleoff: 0
*************************** 16. row ***************************
goods_id: 16
goods_name: PowerEdge T110 II服务器
cate_id: 3
brand_id: 5
goods_price: 5388.000
is_show: 1
is_saleoff: 0
*************************** 17. row ***************************
goods_id: 17
goods_name: Mac Pro MD878CH/A 专业级台式电脑
cate_id: 3
brand_id: 8
goods_price: 28888.000
is_show: 1
is_saleoff: 0
*************************** 18. row ***************************
goods_id: 18
goods_name: HMZ-T3W 头戴显示设备
cate_id: 6
brand_id: 6
goods_price: 6999.000
is_show: 1
is_saleoff: 0
*************************** 19. row ***************************
goods_id: 19
goods_name: 商务双肩背包
cate_id: 6
brand_id: 6
goods_price: 99.000
is_show: 1
is_saleoff: 0
*************************** 20. row ***************************
goods_id: 20
goods_name: X3250 M4机架式服务器 2583i14
cate_id: 3
brand_id: 1
goods_price: 6888.000
is_show: 1
is_saleoff: 0
*************************** 21. row ***************************
goods_id: 21
goods_name: HMZ-T3W 头戴显示设备
cate_id: 6
brand_id: 6
goods_price: 6999.000
is_show: 1
is_saleoff: 0
*************************** 22. row ***************************
goods_id: 22
goods_name: 商务双肩背包
cate_id: 6
brand_id: 6
goods_price: 99.000
is_show: 1
is_saleoff: 0
22 rows in set (0.00 sec)
ERROR:
No query specified
mysql> INSERT tdb_goods_cates(cate_name) VALUES('路由器'),('交换机'),('网卡');
ERROR 1146 (42S02): Table 'world.tdb_goods_cates' doesn't exist
mysql>
mysql> INSERT tdb_goods_brands(brand_name) VALUES('海尔'),('清华同方'),('神舟');
Query OK, 3 rows affected (0.07 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> #在tdb_goods数据表写入任意记录
mysql> INSERT tdb_goods(goods_name,cate_id,brand_id,goods_price)
VALUES(' LaserJet Pro P1606dn 黑白激光打印机','12','4','1849');
Query OK, 1 row affected (0.08 sec)
mysql> SELECT * FROM tdb_goods_cate;
+---------+---------------+
| cate_id | cate_name |
+---------+---------------+
| 1 | 台式机 |
| 2 | 平板电脑 |
| 3 | 服务器/工作站 |
| 4 | 游戏本 |
| 5 | 笔记本 |
| 6 | 笔记本配件 |
| 7 | 超级本 |
+---------+---------------+
7 rows in set (0.03 sec)
mysql> SELECT * FROM tdb_goods\G;
*************************** 1. row ***************************
goods_id: 1
goods_name: R510VC 15.6英寸笔记本
cate_id: 5
brand_id: 2
goods_price: 3399.000
is_show: 1
is_saleoff: 0
*************************** 2. row ***************************
goods_id: 2
goods_name: Y400N 14.0英寸笔记本电脑
cate_id: 5
brand_id: 7
goods_price: 4899.000
is_show: 1
is_saleoff: 0
*************************** 3. row ***************************
goods_id: 3
goods_name: G150TH 15.6英寸游戏本
cate_id: 4
brand_id: 9
goods_price: 8499.000
is_show: 1
is_saleoff: 0
*************************** 4. row ***************************
goods_id: 4
goods_name: X550CC 15.6英寸笔记本
cate_id: 5
brand_id: 2
goods_price: 2799.000
is_show: 1
is_saleoff: 0
*************************** 5. row ***************************
goods_id: 5
goods_name: X240(20ALA0EYCD) 12.5英寸超极本
cate_id: 7
brand_id: 7
goods_price: 4999.000
is_show: 1
is_saleoff: 0
*************************** 6. row ***************************
goods_id: 6
goods_name: U330P 13.3英寸超极本
cate_id: 7
brand_id: 7
goods_price: 4299.000
is_show: 1
is_saleoff: 0
*************************** 7. row ***************************
goods_id: 7
goods_name: SVP13226SCB 13.3英寸触控超极本
cate_id: 7
brand_id: 6
goods_price: 7999.000
is_show: 1
is_saleoff: 0
*************************** 8. row ***************************
goods_id: 8
goods_name: iPad mini MD531CH/A 7.9英寸平板电脑
cate_id: 2
brand_id: 8
goods_price: 1998.000
is_show: 1
is_saleoff: 0
*************************** 9. row ***************************
goods_id: 9
goods_name: iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版）
cate_id: 2
brand_id: 8
goods_price: 3388.000
is_show: 1
is_saleoff: 0
*************************** 10. row ***************************
goods_id: 10
goods_name: iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版）
cate_id: 2
brand_id: 8
goods_price: 2788.000
is_show: 1
is_saleoff: 0
*************************** 11. row ***************************
goods_id: 11
goods_name: IdeaCentre C340 20英寸一体电脑
cate_id: 1
brand_id: 7
goods_price: 3499.000
is_show: 1
is_saleoff: 0
*************************** 12. row ***************************
goods_id: 12
goods_name: Vostro 3800-R1206 台式电脑
cate_id: 1
brand_id: 5
goods_price: 2899.000
is_show: 1
is_saleoff: 0
*************************** 13. row ***************************
goods_id: 13
goods_name: iMac ME086CH/A 21.5英寸一体电脑
cate_id: 1
brand_id: 8
goods_price: 9188.000
is_show: 1
is_saleoff: 0
*************************** 14. row ***************************
goods_id: 14
goods_name: AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ）
cate_id: 1
brand_id: 3
goods_price: 3699.000
is_show: 1
is_saleoff: 0
*************************** 15. row ***************************
goods_id: 15
goods_name: Z220SFF F4F06PA工作站
cate_id: 3
brand_id: 4
goods_price: 4288.000
is_show: 1
is_saleoff: 0
*************************** 16. row ***************************
goods_id: 16
goods_name: PowerEdge T110 II服务器
cate_id: 3
brand_id: 5
goods_price: 5388.000
is_show: 1
is_saleoff: 0
*************************** 17. row ***************************
goods_id: 17
goods_name: Mac Pro MD878CH/A 专业级台式电脑
cate_id: 3
brand_id: 8
goods_price: 28888.000
is_show: 1
is_saleoff: 0
*************************** 18. row ***************************
goods_id: 18
goods_name: HMZ-T3W 头戴显示设备
cate_id: 6
brand_id: 6
goods_price: 6999.000
is_show: 1
is_saleoff: 0
*************************** 19. row ***************************
goods_id: 19
goods_name: 商务双肩背包
cate_id: 6
brand_id: 6
goods_price: 99.000
is_show: 1
is_saleoff: 0
*************************** 20. row ***************************
goods_id: 20
goods_name: X3250 M4机架式服务器 2583i14
cate_id: 3
brand_id: 1
goods_price: 6888.000
is_show: 1
is_saleoff: 0
*************************** 21. row ***************************
goods_id: 21
goods_name: HMZ-T3W 头戴显示设备
cate_id: 6
brand_id: 6
goods_price: 6999.000
is_show: 1
is_saleoff: 0
*************************** 22. row ***************************
goods_id: 22
goods_name: 商务双肩背包
cate_id: 6
brand_id: 6
goods_price: 99.000
is_show: 1
is_saleoff: 0
*************************** 23. row ***************************
goods_id: 23
goods_name: LaserJet Pro P1606dn 黑白激光打印机
cate_id: 12
brand_id: 4
goods_price: 1849.000
is_show: 1
is_saleoff: 0
23 rows in set (0.00 sec)
ERROR:
No query specified
mysql> #数据表参照，用别名；
mysql> #内链接 ，取交集；
mysql> SHOW COLUMNS FROM tdb_goods;
+-------------+------------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+------------------------+------+-----+---------+----------------+
| goods_id | smallint(5) unsigned | NO | PRI | NULL | auto_increment |
| goods_name | varchar(150) | NO | | NULL | |
| cate_id | smallint(5) unsigned | NO | | NULL | |
| brand_id | smallint(5) unsigned | NO | | NULL | |
| goods_price | decimal(15,3) unsigned | NO | | 0.000 | |
| is_show | tinyint(1) | NO | | 1 | |
| is_saleoff | tinyint(1) | NO | | 0 | |
+-------------+------------------------+------+-----+---------+----------------+
7 rows in set (0.00 sec)
mysql> SHOW COLUMNS FROM tdb_goods_cate;
+-----------+----------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+----------------------+------+-----+---------+----------------+
| cate_id | smallint(5) unsigned | NO | PRI | NULL | auto_increment |
| cate_name | varchar(40) | NO | | NULL | |
+-----------+----------------------+------+-----+---------+----------------+
2 rows in set (0.00 sec)
mysql> SELECT goods_id,goods_name,cate_name
-> FROM tdb_goods INNER JOIN tdb_goods_cate
-> ON tdb_goods.cate_id=tdb_goods_cate.cate_id;
+----------+------------------------------------------------------------------------+---------------+
| goods_id | goods_name | cate_name |
+----------+------------------------------------------------------------------------+---------------+
| 1 | R510VC 15.6英寸笔记本 | 笔记本 |
| 2 | Y400N 14.0英寸笔记本电脑 | 笔记本 |
| 3 | G150TH 15.6英寸游戏本 | 游戏本 |
| 4 | X550CC 15.6英寸笔记本 | 笔记本 |
| 5 | X240(20ALA0EYCD) 12.5英寸超极本 | 超级本 |
| 6 | U330P 13.3英寸超极本 | 超级本 |
| 7 | SVP13226SCB 13.3英寸触控超极本 | 超级本 |
| 8 | iPad mini MD531CH/A 7.9英寸平板电脑 | 平板电脑 |
| 9 | iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版） | 平板电脑 |
| 10 | iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版） | 平板电脑 |
| 11 | IdeaCentre C340 20英寸一体电脑 | 台式机 |
| 12 | Vostro 3800-R1206 台式电脑 | 台式机 |
| 13 | iMac ME086CH/A 21.5英寸一体电脑 | 台式机 |
| 14 | AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ） | 台式机 |
| 15 | Z220SFF F4F06PA工作站 | 服务器/工作站 |
| 16 | PowerEdge T110 II服务器 | 服务器/工作站 |
| 17 | Mac Pro MD878CH/A 专业级台式电脑 | 服务器/工作站 |
| 18 | HMZ-T3W 头戴显示设备 | 笔记本配件 |
| 19 | 商务双肩背包 | 笔记本配件 |
| 20 | X3250 M4机架式服务器 2583i14 | 服务器/工作站 |
| 21 | HMZ-T3W 头戴显示设备 | 笔记本配件 |
| 22 | 商务双肩背包 | 笔记本配件 |
+----------+------------------------------------------------------------------------+---------------+
22 rows in set (0.01 sec)
mysql> SELECT * FROM tdb_goods_cate;
+---------+---------------+
| cate_id | cate_name |
+---------+---------------+
| 1 | 台式机 |
| 2 | 平板电脑 |
| 3 | 服务器/工作站 |
| 4 | 游戏本 |
| 5 | 笔记本 |
| 6 | 笔记本配件 |
| 7 | 超级本 |
+---------+---------------+
7 rows in set (0.00 sec)
mysql> #左外连接，取左表中的全部和右表符合条件的部分；
mysql> SELECT goods_id,goods_name,cate_name
-> FROM tdb_goods LEFT JOIN tdb_goods_cate
-> ON tdb_goods.cate_id=tdb_goods_cate.cate_id;
+----------+------------------------------------------------------------------------+---------------+
| goods_id | goods_name | cate_name |
+----------+------------------------------------------------------------------------+---------------+
| 1 | R510VC 15.6英寸笔记本 | 笔记本 |
| 2 | Y400N 14.0英寸笔记本电脑 | 笔记本 |
| 3 | G150TH 15.6英寸游戏本 | 游戏本 |
| 4 | X550CC 15.6英寸笔记本 | 笔记本 |
| 5 | X240(20ALA0EYCD) 12.5英寸超极本 | 超级本 |
| 6 | U330P 13.3英寸超极本 | 超级本 |
| 7 | SVP13226SCB 13.3英寸触控超极本 | 超级本 |
| 8 | iPad mini MD531CH/A 7.9英寸平板电脑 | 平板电脑 |
| 9 | iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版） | 平板电脑 |
| 10 | iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版） | 平板电脑 |
| 11 | IdeaCentre C340 20英寸一体电脑 | 台式机 |
| 12 | Vostro 3800-R1206 台式电脑 | 台式机 |
| 13 | iMac ME086CH/A 21.5英寸一体电脑 | 台式机 |
| 14 | AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ） | 台式机 |
| 15 | Z220SFF F4F06PA工作站 | 服务器/工作站 |
| 16 | PowerEdge T110 II服务器 | 服务器/工作站 |
| 17 | Mac Pro MD878CH/A 专业级台式电脑 | 服务器/工作站 |
| 18 | HMZ-T3W 头戴显示设备 | 笔记本配件 |
| 19 | 商务双肩背包 | 笔记本配件 |
| 20 | X3250 M4机架式服务器 2583i14 | 服务器/工作站 |
| 21 | HMZ-T3W 头戴显示设备 | 笔记本配件 |
| 22 | 商务双肩背包 | 笔记本配件 |
| 23 | LaserJet Pro P1606dn 黑白激光打印机 | NULL |
+----------+------------------------------------------------------------------------+---------------+
23 rows in set (0.00 sec)
mysql> #右外连接，取右表中的全部和左表符合条件的部分；
mysql> SELECT goods_id,goods_name,cate_name
-> FROM tdb_goods RIGHT JOIN tdb_goods_cate
-> ON tdb_goods.cate_id=tdb_goods_cate.cate_id;
+----------+------------------------------------------------------------------------+---------------+
| goods_id | goods_name | cate_name |
+----------+------------------------------------------------------------------------+---------------+
| 1 | R510VC 15.6英寸笔记本 | 笔记本 |
| 2 | Y400N 14.0英寸笔记本电脑 | 笔记本 |
| 3 | G150TH 15.6英寸游戏本 | 游戏本 |
| 4 | X550CC 15.6英寸笔记本 | 笔记本 |
| 5 | X240(20ALA0EYCD) 12.5英寸超极本 | 超级本 |
| 6 | U330P 13.3英寸超极本 | 超级本 |
| 7 | SVP13226SCB 13.3英寸触控超极本 | 超级本 |
| 8 | iPad mini MD531CH/A 7.9英寸平板电脑 | 平板电脑 |
| 9 | iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版） | 平板电脑 |
| 10 | iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版） | 平板电脑 |
| 11 | IdeaCentre C340 20英寸一体电脑 | 台式机 |
| 12 | Vostro 3800-R1206 台式电脑 | 台式机 |
| 13 | iMac ME086CH/A 21.5英寸一体电脑 | 台式机 |
| 14 | AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ） | 台式机 |
| 15 | Z220SFF F4F06PA工作站 | 服务器/工作站 |
| 16 | PowerEdge T110 II服务器 | 服务器/工作站 |
| 17 | Mac Pro MD878CH/A 专业级台式电脑 | 服务器/工作站 |
| 18 | HMZ-T3W 头戴显示设备 | 笔记本配件 |
| 19 | 商务双肩背包 | 笔记本配件 |
| 20 | X3250 M4机架式服务器 2583i14 | 服务器/工作站 |
| 21 | HMZ-T3W 头戴显示设备 | 笔记本配件 |
| 22 | 商务双肩背包 | 笔记本配件 |
+----------+------------------------------------------------------------------------+---------------+
22 rows in set (0.02 sec)
mysql> SELECT goods_id,goods_name,cate_name
-> FROM tdb_goods LEFT JOIN tdb_goods_cate
-> ON tdb_goods.cate_id=tdb_goods_cate.cate_id\G;
*************************** 1. row ***************************
goods_id: 1
goods_name: R510VC 15.6英寸笔记本
cate_name: 笔记本
*************************** 2. row ***************************
goods_id: 2
goods_name: Y400N 14.0英寸笔记本电脑
cate_name: 笔记本
*************************** 3. row ***************************
goods_id: 3
goods_name: G150TH 15.6英寸游戏本
cate_name: 游戏本
*************************** 4. row ***************************
goods_id: 4
goods_name: X550CC 15.6英寸笔记本
cate_name: 笔记本
*************************** 5. row ***************************
goods_id: 5
goods_name: X240(20ALA0EYCD) 12.5英寸超极本
cate_name: 超级本
*************************** 6. row ***************************
goods_id: 6
goods_name: U330P 13.3英寸超极本
cate_name: 超级本
*************************** 7. row ***************************
goods_id: 7
goods_name: SVP13226SCB 13.3英寸触控超极本
cate_name: 超级本
*************************** 8. row ***************************
goods_id: 8
goods_name: iPad mini MD531CH/A 7.9英寸平板电脑
cate_name: 平板电脑
*************************** 9. row ***************************
goods_id: 9
goods_name: iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版）
cate_name: 平板电脑
*************************** 10. row ***************************
goods_id: 10
goods_name: iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版）
cate_name: 平板电脑
*************************** 11. row ***************************
goods_id: 11
goods_name: IdeaCentre C340 20英寸一体电脑
cate_name: 台式机
*************************** 12. row ***************************
goods_id: 12
goods_name: Vostro 3800-R1206 台式电脑
cate_name: 台式机
*************************** 13. row ***************************
goods_id: 13
goods_name: iMac ME086CH/A 21.5英寸一体电脑
cate_name: 台式机
*************************** 14. row ***************************
goods_id: 14
goods_name: AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ）
cate_name: 台式机
*************************** 15. row ***************************
goods_id: 15
goods_name: Z220SFF F4F06PA工作站
cate_name: 服务器/工作站
*************************** 16. row ***************************
goods_id: 16
goods_name: PowerEdge T110 II服务器
cate_name: 服务器/工作站
*************************** 17. row ***************************
goods_id: 17
goods_name: Mac Pro MD878CH/A 专业级台式电脑
cate_name: 服务器/工作站
*************************** 18. row ***************************
goods_id: 18
goods_name: HMZ-T3W 头戴显示设备
cate_name: 笔记本配件
*************************** 19. row ***************************
goods_id: 19
goods_name: 商务双肩背包
cate_name: 笔记本配件
*************************** 20. row ***************************
goods_id: 20
goods_name: X3250 M4机架式服务器 2583i14
cate_name: 服务器/工作站
*************************** 21. row ***************************
goods_id: 21
goods_name: HMZ-T3W 头戴显示设备
cate_name: 笔记本配件
*************************** 22. row ***************************
goods_id: 22
goods_name: 商务双肩背包
cate_name: 笔记本配件
*************************** 23. row ***************************
goods_id: 23
goods_name: LaserJet Pro P1606dn 黑白激光打印机
cate_name: NULL
23 rows in set (0.00 sec)
ERROR:
No query specified
mysql> #多表连接；
mysql> SHOW COLUMNS FROM tdb_goods\G;
*************************** 1. row ***************************
Field: goods_id
Type: smallint(5) unsigned
Null: NO
Key: PRI
Default: NULL
Extra: auto_increment
*************************** 2. row ***************************
Field: goods_name
Type: varchar(150)
Null: NO
Key:
Default: NULL
Extra:
*************************** 3. row ***************************
Field: cate_id
Type: smallint(5) unsigned
Null: NO
Key:
Default: NULL
Extra:
*************************** 4. row ***************************
Field: brand_id
Type: smallint(5) unsigned
Null: NO
Key:
Default: NULL
Extra:
*************************** 5. row ***************************
Field: goods_price
Type: decimal(15,3) unsigned
Null: NO
Key:
Default: 0.000
Extra:
*************************** 6. row ***************************
Field: is_show
Type: tinyint(1)
Null: NO
Key:
Default: 1
Extra:
*************************** 7. row ***************************
Field: is_saleoff
Type: tinyint(1)
Null: NO
Key:
Default: 0
Extra:
7 rows in set (0.00 sec)
ERROR:
No query specified
mysql> #实现三张表的连接；
mysql> SELECT goods_id,goods_name,cate_name,brand_name,goods_price FROM tdb_goods AS g
-> INNER JOIN tdb_goods_cate AS c
-> ON g.cate_id=c.cate_id
-> INNER JOIN tdb_goods_brands AS b
-> ON g.brand_id=b.brand_id\G;
*************************** 1. row ***************************
goods_id: 1
goods_name: R510VC 15.6英寸笔记本
cate_name: 笔记本
brand_name: 华硕
goods_price: 3399.000
*************************** 2. row ***************************
goods_id: 2
goods_name: Y400N 14.0英寸笔记本电脑
cate_name: 笔记本
brand_name: 联想
goods_price: 4899.000
*************************** 3. row ***************************
goods_id: 3
goods_name: G150TH 15.6英寸游戏本
cate_name: 游戏本
brand_name: 雷神
goods_price: 8499.000
*************************** 4. row ***************************
goods_id: 4
goods_name: X550CC 15.6英寸笔记本
cate_name: 笔记本
brand_name: 华硕
goods_price: 2799.000
*************************** 5. row ***************************
goods_id: 5
goods_name: X240(20ALA0EYCD) 12.5英寸超极本
cate_name: 超级本
brand_name: 联想
goods_price: 4999.000
*************************** 6. row ***************************
goods_id: 6
goods_name: U330P 13.3英寸超极本
cate_name: 超级本
brand_name: 联想
goods_price: 4299.000
*************************** 7. row ***************************
goods_id: 7
goods_name: SVP13226SCB 13.3英寸触控超极本
cate_name: 超级本
brand_name: 索尼
goods_price: 7999.000
*************************** 8. row ***************************
goods_id: 8
goods_name: iPad mini MD531CH/A 7.9英寸平板电脑
cate_name: 平板电脑
brand_name: 苹果
goods_price: 1998.000
*************************** 9. row ***************************
goods_id: 9
goods_name: iPad Air MD788CH/A 9.7英寸平板电脑 （16G WiFi版）
cate_name: 平板电脑
brand_name: 苹果
goods_price: 3388.000
*************************** 10. row ***************************
goods_id: 10
goods_name: iPad mini ME279CH/A 配备 Retina 显示屏 7.9英寸平板电脑 （16G WiFi版）
cate_name: 平板电脑
brand_name: 苹果
goods_price: 2788.000
*************************** 11. row ***************************
goods_id: 11
goods_name: IdeaCentre C340 20英寸一体电脑
cate_name: 台式机
brand_name: 联想
goods_price: 3499.000
*************************** 12. row ***************************
goods_id: 12
goods_name: Vostro 3800-R1206 台式电脑
cate_name: 台式机
brand_name: 戴尔
goods_price: 2899.000
*************************** 13. row ***************************
goods_id: 13
goods_name: iMac ME086CH/A 21.5英寸一体电脑
cate_name: 台式机
brand_name: 苹果
goods_price: 9188.000
*************************** 14. row ***************************
goods_id: 14
goods_name: AT7-7414LP 台式电脑 （i5-3450四核 4G 500G 2G独显 DVD 键鼠 Linux ）
cate_name: 台式机
brand_name: 宏碁
goods_price: 3699.000
*************************** 15. row ***************************
goods_id: 15
goods_name: Z220SFF F4F06PA工作站
cate_name: 服务器/工作站
brand_name: 惠普
goods_price: 4288.000
*************************** 16. row ***************************
goods_id: 16
goods_name: PowerEdge T110 II服务器
cate_name: 服务器/工作站
brand_name: 戴尔
goods_price: 5388.000
*************************** 17. row ***************************
goods_id: 17
goods_name: Mac Pro MD878CH/A 专业级台式电脑
cate_name: 服务器/工作站
brand_name: 苹果
goods_price: 28888.000
*************************** 18. row ***************************
goods_id: 18
goods_name: HMZ-T3W 头戴显示设备
cate_name: 笔记本配件
brand_name: 索尼
goods_price: 6999.000
*************************** 19. row ***************************
goods_id: 19
goods_name: 商务双肩背包
cate_name: 笔记本配件
brand_name: 索尼
goods_price: 99.000
*************************** 20. row ***************************
goods_id: 20
goods_name: X3250 M4机架式服务器 2583i14
cate_name: 服务器/工作站
brand_name: IBM
goods_price: 6888.000
*************************** 21. row ***************************
goods_id: 21
goods_name: HMZ-T3W 头戴显示设备
cate_name: 笔记本配件
brand_name: 索尼
goods_price: 6999.000
*************************** 22. row ***************************
goods_id: 22
goods_name: 商务双肩背包
cate_name: 笔记本配件
brand_name: 索尼
goods_price: 99.000
22 rows in set (0.02 sec)
ERROR:
No query specified
mysql>
mysql> #SHOW COLUMNS FROM tdb_goods_cate;
mysql> SHOW COLUMNS FROM tdb_goods_cate;
+-----------+----------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+----------------------+------+-----+---------+----------------+
| cate_id | smallint(5) unsigned | NO | PRI | NULL | auto_increment |
| cate_name | varchar(40) | NO | | NULL | |
+-----------+----------------------+------+-----+---------+----------------+
2 rows in set (0.00 sec)
mysql> SELECT * FROM tdb_goods_cate;
+---------+---------------+
| cate_id | cate_name |
+---------+---------------+
| 1 | 台式机 |
| 2 | 平板电脑 |
| 3 | 服务器/工作站 |
| 4 | 游戏本 |
| 5 | 笔记本 |
| 6 | 笔记本配件 |
| 7 | 超级本 |
+---------+---------------+
7 rows in set (0.00 sec)
mysql> CREATE TABLE tdb_goods_types(
-> type_id SMALLINT UNSIGNED PRIMARY KEY AUTO_INCREMENT,
-> type_name VARCHAR(20) NOT NULL,
-> parent_id SMALLINT UNSIGNED NOT NULL DEFAULT 0
-> );
Query OK, 0 rows affected (0.19 sec)
mysql> INSERT tdb_goods_types(type_name,parent_id) VALUES('家用电器',DEFAULT);
Query OK, 1 row affected (0.05 sec)
mysql> INSERT tdb_goods_types(type_name,parent_id) VALUES('电脑、办公',DEFAULT);
Query OK, 1 row affected (0.02 sec)
mysql> INSERT tdb_goods_types(type_name,parent_id) VALUES('大家电',1);
Query OK, 1 row affected (0.06 sec)
mysql> INSERT tdb_goods_types(type_name,parent_id) VALUES('生活电器',1);
Query OK, 1 row affected (0.05 sec)
mysql> INSERT tdb_goods_types(type_name,parent_id) VALUES('平板电视',3);
Query OK, 1 row affected (0.02 sec)
mysql> INSERT tdb_goods_types(type_name,parent_id) VALUES('空调',3);
Query OK, 1 row affected (0.02 sec)
mysql> INSERT tdb_goods_types(type_name,parent_id) VALUES('电风扇',4);
Query OK, 1 row affected (0.02 sec)
mysql> INSERT tdb_goods_types(tyCopy after login
以上就是MySQL基础五：子查询与链接_MySQL的内容，更多相关内容请关注PHP中文网（www.php.cn）！
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How to open phpmyadmin
Apr 10, 2025 pm 10:51 PM
You can open phpMyAdmin through the following steps: 1. Log in to the website control panel; 2. Find and click the phpMyAdmin icon; 3. Enter MySQL credentials; 4. Click "Login".
MySQL: An Introduction to the World's Most Popular Database
Apr 12, 2025 am 12:18 AM
MySQL is an open source relational database management system, mainly used to store and retrieve data quickly and reliably. Its working principle includes client requests, query resolution, execution of queries and return results. Examples of usage include creating tables, inserting and querying data, and advanced features such as JOIN operations. Common errors involve SQL syntax, data types, and permissions, and optimization suggestions include the use of indexes, optimized queries, and partitioning of tables.
How to use single threaded redis
Apr 10, 2025 pm 07:12 PM
Redis uses a single threaded architecture to provide high performance, simplicity, and consistency. It utilizes I/O multiplexing, event loops, non-blocking I/O, and shared memory to improve concurrency, but with limitations of concurrency limitations, single point of failure, and unsuitable for write-intensive workloads.
MySQL's Place: Databases and Programming
Apr 13, 2025 am 12:18 AM
MySQL's position in databases and programming is very important. It is an open source relational database management system that is widely used in various application scenarios. 1) MySQL provides efficient data storage, organization and retrieval functions, supporting Web, mobile and enterprise-level systems. 2) It uses a client-server architecture, supports multiple storage engines and index optimization. 3) Basic usages include creating tables and inserting data, and advanced usages involve multi-table JOINs and complex queries. 4) Frequently asked questions such as SQL syntax errors and performance issues can be debugged through the EXPLAIN command and slow query log. 5) Performance optimization methods include rational use of indexes, optimized query and use of caches. Best practices include using transactions and PreparedStatemen
Why Use MySQL? Benefits and Advantages
Apr 12, 2025 am 12:17 AM
MySQL is chosen for its performance, reliability, ease of use, and community support. 1.MySQL provides efficient data storage and retrieval functions, supporting multiple data types and advanced query operations. 2. Adopt client-server architecture and multiple storage engines to support transaction and query optimization. 3. Easy to use, supports a variety of operating systems and programming languages. 4. Have strong community support and provide rich resources and solutions.
Monitor Redis Droplet with Redis Exporter Service
Apr 10, 2025 pm 01:36 PM
Effective monitoring of Redis databases is critical to maintaining optimal performance, identifying potential bottlenecks, and ensuring overall system reliability. Redis Exporter Service is a powerful utility designed to monitor Redis databases using Prometheus. This tutorial will guide you through the complete setup and configuration of Redis Exporter Service, ensuring you seamlessly build monitoring solutions. By studying this tutorial, you will achieve fully operational monitoring settings
How to view sql database error
Apr 10, 2025 pm 12:09 PM
The methods for viewing SQL database errors are: 1. View error messages directly; 2. Use SHOW ERRORS and SHOW WARNINGS commands; 3. Access the error log; 4. Use error codes to find the cause of the error; 5. Check the database connection and query syntax; 6. Use debugging tools.
How to connect to the database of apache
Apr 13, 2025 pm 01:03 PM
Apache connects to a database requires the following steps: Install the database driver. Configure the web.xml file to create a connection pool. Create a JDBC data source and specify the connection settings. Use the JDBC API to access the database from Java code, including getting connections, creating statements, binding parameters, executing queries or updates, and processing results.
