Heim >Datenbank >MySQL-Tutorial >MySQL基础五:子查询与链接_MySQL
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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 specified
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(ty
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