MySQL基礎

時間 2019-11-21

標籤 mysql 基礎欄目 MySQL 简体版

原文原文鏈接

目錄mysql

第3章使用MySQL

入門命令

# 返回表的每個字段 
mysql> show columns from customers;
+--------------+-----------+------+-----+---------+----------------+
| Field        | Type      | Null | Key | Default | Extra          |
+--------------+-----------+------+-----+---------+----------------+
| cust_id      | int(11)   | NO   | PRI | NULL    | auto_increment |
| cust_name    | char(50)  | NO   |     | NULL    |                |
| cust_address | char(50)  | YES  |     | NULL    |                |
| cust_city    | char(50)  | YES  |     | NULL    |                |
| cust_state   | char(5)   | YES  |     | NULL    |                |
| cust_zip     | char(10)  | YES  |     | NULL    |                |
| cust_country | char(50)  | YES  |     | NULL    |                |
| cust_contact | char(50)  | YES  |     | NULL    |                |
| cust_email   | char(255) | YES  |     | NULL    |                |
+--------------+-----------+------+-----+---------+----------------+
9 rows in set (0.00 sec)

# 還可使用describe語句
mysql> describe customers;
+--------------+-----------+------+-----+---------+----------------+
| Field        | Type      | Null | Key | Default | Extra          |
+--------------+-----------+------+-----+---------+----------------+
| cust_id      | int(11)   | NO   | PRI | NULL    | auto_increment |
| cust_name    | char(50)  | NO   |     | NULL    |                |
| cust_address | char(50)  | YES  |     | NULL    |                |
| cust_city    | char(50)  | YES  |     | NULL    |                |
| cust_state   | char(5)   | YES  |     | NULL    |                |
| cust_zip     | char(10)  | YES  |     | NULL    |                |
| cust_country | char(50)  | YES  |     | NULL    |                |
| cust_contact | char(50)  | YES  |     | NULL    |                |
| cust_email   | char(255) | YES  |     | NULL    |                |
+--------------+-----------+------+-----+---------+----------------+
9 rows in set (0.00 sec)

# 顯示建立數據庫的語句
mysql> show create database sys;
+----------+--------------------------------------------------------------+
| Database | Create Database                                              |
+----------+--------------------------------------------------------------+
| sys      | CREATE DATABASE `sys` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+--------------------------------------------------------------+
1 row in set (0.00 sec)



# 顯示建立數據庫表的語句
mysql> show create table customers;
+-----------+----+
| Table     | Create Table                                             
+-----------+----+
| customers | CREATE TABLE `customers` (
  `cust_id` int(11) NOT NULL AUTO_INCREMENT,
  `cust_name` char(50) NOT NULL,
  `cust_address` char(50) DEFAULT NULL,
  `cust_city` char(50) DEFAULT NULL,
  `cust_state` char(5) DEFAULT NULL,
  `cust_zip` char(10) DEFAULT NULL,
  `cust_country` char(50) DEFAULT NULL,
  `cust_contact` char(50) DEFAULT NULL,
  `cust_email` char(255) DEFAULT NULL,
  PRIMARY KEY (`cust_id`)
) ENGINE=InnoDB AUTO_INCREMENT=10006 DEFAULT CHARSET=utf8 
+-----------+----+
1 row in set (0.00 sec)

第4章檢索數據

檢索單列

mysql> select prod_name from products;
+----------------+
| prod_name      |
+----------------+
| .5 ton anvil   |
| 1 ton anvil    |
| 2 ton anvil    |
| Detonator      |
| Bird seed      |
| Carrots        |
| Fuses          |
| JetPack 1000   |
| JetPack 2000   |
| Oil can        |
| Safe           |
| Sling          |
| TNT (1 stick)  |
| TNT (5 sticks) |
+----------------+
14 rows in set (0.00 sec)

檢索多列

mysql> select prod_id, prod_name, prod_price from products;
+---------+----------------+------------+
| prod_id | prod_name      | prod_price |
+---------+----------------+------------+
| ANV01   | .5 ton anvil   |       5.99 |
| ANV02   | 1 ton anvil    |       9.99 |
| ANV03   | 2 ton anvil    |      14.99 |
| DTNTR   | Detonator      |      13.00 |
| FB      | Bird seed      |      10.00 |
| FC      | Carrots        |       2.50 |
| FU1     | Fuses          |       3.42 |
| JP1000  | JetPack 1000   |      35.00 |
| JP2000  | JetPack 2000   |      55.00 |
| OL1     | Oil can        |       8.99 |
| SAFE    | Safe           |      50.00 |
| SLING   | Sling          |       4.49 |
| TNT1    | TNT (1 stick)  |       2.50 |
| TNT2    | TNT (5 sticks) |      10.00 |
+---------+----------------+------------+
14 rows in set (0.00 sec)

檢索全部列

mysql> select * from products;
+---------+---------+----------------+------------+----------------------------------------------------------------+
| prod_id | vend_id | prod_name      | prod_price | prod_desc                                                      |
+---------+---------+----------------+------------+----------------------------------------------------------------+
| ANV01   |    1001 | .5 ton anvil   |       5.99 | .5 ton anvil, black, complete with handy hook                  |
| ANV02   |    1001 | 1 ton anvil    |       9.99 | 1 ton anvil, black, complete with handy hook and carrying case |
| ANV03   |    1001 | 2 ton anvil    |      14.99 | 2 ton anvil, black, complete with handy hook and carrying case |
| DTNTR   |    1003 | Detonator      |      13.00 | Detonator (plunger powered), fuses not included                |
| FB      |    1003 | Bird seed      |      10.00 | Large bag (suitable for road runners)                          |
| FC      |    1003 | Carrots        |       2.50 | Carrots (rabbit hunting season only)                           |
| FU1     |    1002 | Fuses          |       3.42 | 1 dozen, extra long                                            |
| JP1000  |    1005 | JetPack 1000   |      35.00 | JetPack 1000, intended for single use                          |
| JP2000  |    1005 | JetPack 2000   |      55.00 | JetPack 2000, multi-use                                        |
| OL1     |    1002 | Oil can        |       8.99 | Oil can, red                                                   |
| SAFE    |    1003 | Safe           |      50.00 | Safe with combination lock                                     |
| SLING   |    1003 | Sling          |       4.49 | Sling, one size fits all                                       |
| TNT1    |    1003 | TNT (1 stick)  |       2.50 | TNT, red, single stick                                         |
| TNT2    |    1003 | TNT (5 sticks) |      10.00 | TNT, red, pack of 10 sticks                                    |
+---------+---------+----------------+------------+----------------------------------------------------------------+
14 rows in set (0.00 sec)

檢索不一樣的行

mysql> select distinct vend_id from products;
+---------+
| vend_id |
+---------+
|    1001 |
|    1002 |
|    1003 |
|    1005 |
+---------+
4 rows in set (0.00 sec)

限制結果

# 從第0行開始，顯示3行
mysql> select distinct vend_id from products limit 3;
# 或者 select distinct vend_id from products limit 0, 3;
# 或者 select distinct vend_id from products limit 3 offset 0;
+---------+
| vend_id |
+---------+
|    1001 |
|    1002 |
|    1003 |
+---------+
3 rows in set (0.00 sec)

第5章排序檢索

排序數據

mysql> select prod_name from products order by prod_name;
+----------------+
| prod_name      |
+----------------+
| .5 ton anvil   |
| 1 ton anvil    |
| 2 ton anvil    |
| Bird seed      |
| Carrots        |
| Detonator      |
| Fuses          |
| JetPack 1000   |
| JetPack 2000   |
| Oil can        |
| Safe           |
| Sling          |
| TNT (1 stick)  |
| TNT (5 sticks) |
+----------------+

按多個列排序

mysql> select prod_id, prod_price, prod_name from products order by prod_price, prod_name;
+---------+------------+----------------+
| prod_id | prod_price | prod_name      |
+---------+------------+----------------+
| FC      |       2.50 | Carrots        |
| TNT1    |       2.50 | TNT (1 stick)  |
| FU1     |       3.42 | Fuses          |
| SLING   |       4.49 | Sling          |
| ANV01   |       5.99 | .5 ton anvil   |
| OL1     |       8.99 | Oil can        |
| ANV02   |       9.99 | 1 ton anvil    |
| FB      |      10.00 | Bird seed      |
| TNT2    |      10.00 | TNT (5 sticks) |
| DTNTR   |      13.00 | Detonator      |
| ANV03   |      14.99 | 2 ton anvil    |
| JP1000  |      35.00 | JetPack 1000   |
| SAFE    |      50.00 | Safe           |
| JP2000  |      55.00 | JetPack 2000   |
+---------+------------+----------------+
14 rows in set (0.00 sec)

指定排序方向

mysql> select prod_id, prod_price, prod_name from products order by prod_price desc;
+---------+------------+----------------+
| prod_id | prod_price | prod_name      |
+---------+------------+----------------+
| JP2000  |      55.00 | JetPack 2000   |
| SAFE    |      50.00 | Safe           |
| JP1000  |      35.00 | JetPack 1000   |
| ANV03   |      14.99 | 2 ton anvil    |
| DTNTR   |      13.00 | Detonator      |
| FB      |      10.00 | Bird seed      |
| TNT2    |      10.00 | TNT (5 sticks) |
| ANV02   |       9.99 | 1 ton anvil    |
| OL1     |       8.99 | Oil can        |
| ANV01   |       5.99 | .5 ton anvil   |
| SLING   |       4.49 | Sling          |
| FU1     |       3.42 | Fuses          |
| FC      |       2.50 | Carrots        |
| TNT1    |       2.50 | TNT (1 stick)  |
+---------+------------+----------------+
14 rows in set (0.00 sec)

order by 和 limit 組合使用

mysql> select prod_id, prod_price, prod_name from products order by prod_price desc limit 3 offset 0;
+---------+------------+--------------+
| prod_id | prod_price | prod_name    |
+---------+------------+--------------+
| JP2000  |      55.00 | JetPack 2000 |
| SAFE    |      50.00 | Safe         |
| JP1000  |      35.00 | JetPack 1000 |
+---------+------------+--------------+
3 rows in set (0.00 sec)

第6章過濾數據

檢查單個值

mysql> select prod_name, prod_price from products where prod_name='fuses';
+-----------+------------+
| prod_name | prod_price |
+-----------+------------+
| Fuses     |       3.42 |
+-----------+------------+
1 row in set (0.00 sec)

不匹配檢查

mysql> select vend_id, prod_name from products where vend_id <> 1003;
+---------+--------------+
| vend_id | prod_name    |
+---------+--------------+
|    1001 | .5 ton anvil |
|    1001 | 1 ton anvil  |
|    1001 | 2 ton anvil  |
|    1002 | Fuses        |
|    1005 | JetPack 1000 |
|    1005 | JetPack 2000 |
|    1002 | Oil can      |
+---------+--------------+
7 rows in set (0.00 sec)

範圍值檢查

mysql> select prod_price, prod_name from products where prod_price between 5 and 10;
+------------+----------------+
| prod_price | prod_name      |
+------------+----------------+
|       5.99 | .5 ton anvil   |
|       9.99 | 1 ton anvil    |
|      10.00 | Bird seed      |
|       8.99 | Oil can        |
|      10.00 | TNT (5 sticks) |
+------------+----------------+
5 rows in set (0.00 sec)

空值檢查

mysql> select cust_name, cust_email from customers where cust_email is null;
+-------------+------------+
| cust_name   | cust_email |
+-------------+------------+
| Mouse House | NULL       |
| E Fudd      | NULL       |
+-------------+------------+
2 rows in set (0.00 sec)

第7章數據過濾

組合where子句

and操做符

mysql> select prod_name, vend_id, prod_price from products where vend_id = 1003 and prod_price < 5;
+---------------+---------+------------+
| prod_name     | vend_id | prod_price |
+---------------+---------+------------+
| Carrots       |    1003 |       2.50 |
| Sling         |    1003 |       4.49 |
| TNT (1 stick) |    1003 |       2.50 |
+---------------+---------+------------+
3 rows in set (0.01 sec)

or操做符

mysql> select prod_name, vend_id, prod_price from products where vend_id = 1003 or prod_price < 5;
+----------------+---------+------------+
| prod_name      | vend_id | prod_price |
+----------------+---------+------------+
| Detonator      |    1003 |      13.00 |
| Bird seed      |    1003 |      10.00 |
| Carrots        |    1003 |       2.50 |
| Fuses          |    1002 |       3.42 |
| Safe           |    1003 |      50.00 |
| Sling          |    1003 |       4.49 |
| TNT (1 stick)  |    1003 |       2.50 |
| TNT (5 sticks) |    1003 |      10.00 |
+----------------+---------+------------+
8 rows in set (0.00 sec)

計算次序

# and 優先級高於or
# 找出vend_id爲1002或1003，而且prod_id大於等於10的產品
mysql> select prod_name, vend_id, prod_price from products where (vend_id = 1003 or vend_id = 1002) and prod_price >= 10;
+----------------+---------+------------+
| prod_name      | vend_id | prod_price |
+----------------+---------+------------+
| Detonator      |    1003 |      13.00 |
| Bird seed      |    1003 |      10.00 |
| Safe           |    1003 |      50.00 |
| TNT (5 sticks) |    1003 |      10.00 |
+----------------+---------+------------+
4 rows in set (0.00 sec)

in操做符

mysql> select prod_name, vend_id, prod_price from products where vend_id in (1002, 1003) order by prod_price desc;
+----------------+---------+------------+
| prod_name      | vend_id | prod_price |
+----------------+---------+------------+
| Safe           |    1003 |      50.00 |
| Detonator      |    1003 |      13.00 |
| Bird seed      |    1003 |      10.00 |
| TNT (5 sticks) |    1003 |      10.00 |
| Oil can        |    1002 |       8.99 |
| Sling          |    1003 |       4.49 |
| Fuses          |    1002 |       3.42 |
| Carrots        |    1003 |       2.50 |
| TNT (1 stick)  |    1003 |       2.50 |
+----------------+---------+------------+
9 rows in set (0.00 sec)

not操做符

mysql> select prod_name, vend_id, prod_price from products where vend_id not in (1002, 1003) order by prod_price desc;
+--------------+---------+------------+
| prod_name    | vend_id | prod_price |
+--------------+---------+------------+
| JetPack 2000 |    1005 |      55.00 |
| JetPack 1000 |    1005 |      35.00 |
| 2 ton anvil  |    1001 |      14.99 |
| 1 ton anvil  |    1001 |       9.99 |
| .5 ton anvil |    1001 |       5.99 |
+--------------+---------+------------+
5 rows in set (0.00 sec)

第8章使用通配符進行過濾

%通配符

# %表示任何字符出現任意次數【0、一、多】次
mysql> select prod_name, prod_price from products where prod_name like 'jet%';
+--------------+------------+
| prod_name    | prod_price |
+--------------+------------+
| JetPack 1000 |      35.00 |
| JetPack 2000 |      55.00 |
+--------------+------------+
2 rows in set (0.00 sec)

_通配符

# _通配符和%同樣，只是_只匹配一個字符而不是多個字符
mysql> select prod_id, prod_name, prod_price from products where prod_name like '_ ton anvil';
+---------+-------------+------------+
| prod_id | prod_name   | prod_price |
+---------+-------------+------------+
| ANV02   | 1 ton anvil |       9.99 |
| ANV03   | 2 ton anvil |      14.99 |
+---------+-------------+------------+

第9章用正則表達式進行搜索

基本字符匹配

mysql> select prod_name, prod_price from products where prod_name regexp '1000';
+--------------+------------+
| prod_name    | prod_price |
+--------------+------------+
| JetPack 1000 |      35.00 |
+--------------+------------+
1 row in set (0.00 sec)

mysql> select prod_name, prod_price from products where prod_name regexp '.000' order by prod_price desc;
+--------------+------------+
| prod_name    | prod_price |
+--------------+------------+
| JetPack 2000 |      55.00 |
| JetPack 1000 |      35.00 |
+--------------+------------+
2 rows in set (0.00 sec)

進行OR匹配

mysql> select prod_name, prod_price from products where prod_name regexp '1000|2000' order by prod_price desc;
+--------------+------------+
| prod_name    | prod_price |
+--------------+------------+
| JetPack 2000 |      55.00 |
| JetPack 1000 |      35.00 |
+--------------+------------+
2 rows in set (0.00 sec)

匹配幾個字符之一

mysql> select prod_name, prod_price from products where prod_name regexp '[123] ton' order by prod_price desc;
+-------------+------------+
| prod_name   | prod_price |
+-------------+------------+
| 2 ton anvil |      14.99 |
| 1 ton anvil |       9.99 |
+-------------+------------+
2 rows in set (0.00 sec)

匹配範圍

mysql> select prod_name, prod_price from products where prod_name regexp '[1-5] ton' order by prod_price desc;
+--------------+------------+
| prod_name    | prod_price |
+--------------+------------+
| 2 ton anvil  |      14.99 |
| 1 ton anvil  |       9.99 |
| .5 ton anvil |       5.99 |
+--------------+------------+
3 rows in set (0.00 sec)

匹配特殊字符

mysql> select prod_name, prod_price from products where prod_name regexp '\\.';
+--------------+------------+
| prod_name    | prod_price |
+--------------+------------+
| .5 ton anvil |       5.99 |
+--------------+------------+
1 row in set (0.00 sec)

匹配多個實例

mysql> select prod_name, prod_price from products where prod_name regexp '\\([0-9] sticks?\\)';
+----------------+------------+
| prod_name      | prod_price |
+----------------+------------+
| TNT (1 stick)  |       2.50 |
| TNT (5 sticks) |      10.00 |
+----------------+------------+
2 rows in set (0.00 sec)

定位符

mysql> select prod_name, prod_price from products where prod_name regexp '^[0-9\\.]';
+--------------+------------+
| prod_name    | prod_price |
+--------------+------------+
| .5 ton anvil |       5.99 |
| 1 ton anvil  |       9.99 |
| 2 ton anvil  |      14.99 |
+--------------+------------+
3 rows in set (0.00 sec)

第10章建立可計算字段

拼接字段

mysql> select Concat(vend_name, ' (', vend_country, ')') from vendors order by vend_name;
+--------------------------------------------+
| Concat(vend_name, ' (', vend_country, ')') |
+--------------------------------------------+
| ACME (USA)                                 |
| Anvils R Us (USA)                          |
| Furball Inc. (USA)                         |
| Jet Set (England)                          |
| Jouets Et Ours (France)                    |
| LT Supplies (USA)                          |
+--------------------------------------------+
6 rows in set (0.00 sec)

# Trim函數 MySQL除了支持RTrim()（正如剛纔所見，它去掉
# 串右邊的空格），還支持LTrim()（去掉串左邊的空格）以及
# Trim()（去掉串左右兩邊的空格）。

使用別名

mysql> select Concat(vend_name, ' (', vend_country, ')') as vend_title from vendors order by vend_name;
+-------------------------+
| vend_title              |
+-------------------------+
| ACME (USA)              |
| Anvils R Us (USA)       |
| Furball Inc. (USA)      |
| Jet Set (England)       |
| Jouets Et Ours (France) |
| LT Supplies (USA)       |
+-------------------------+
6 rows in set (0.00 sec)

執行算數計算

mysql> select prod_id, quantity, item_price, quantity*item_price as expanded_price from orderitems where order_num='20005';
+---------+----------+------------+----------------+
| prod_id | quantity | item_price | expanded_price |
+---------+----------+------------+----------------+
| ANV01   |       10 |       5.99 |          59.90 |
| ANV02   |        3 |       9.99 |          29.97 |
| TNT2    |        5 |      10.00 |          50.00 |
| FB      |        1 |      10.00 |          10.00 |
+---------+----------+------------+----------------+
4 rows in set (0.00 sec)

第11章使用數據處理函數

文本處理函數

mysql> select prod_name, Upper(prod_name), prod_price from products where prod_name regexp '.000';
+--------------+------------------+------------+
| prod_name    | Upper(prod_name) | prod_price |
+--------------+------------------+------------+
| JetPack 1000 | JETPACK 1000     |      35.00 |
| JetPack 2000 | JETPACK 2000     |      55.00 |
+--------------+------------------+------------+
2 rows in set (0.00 sec)

日期和時間處理函數

mysql> select order_date, cust_id from orders where Date(order_date) = '2005-09-01';
+---------------------+---------+
| order_date          | cust_id |
+---------------------+---------+
| 2005-09-01 00:00:00 |   10001 |
+---------------------+---------+
1 row in set (0.00 sec)

mysql> select order_date, cust_id from orders where Year(order_date) = '2005' and Month(order_date) = '09';
+---------------------+---------+
| order_date          | cust_id |
+---------------------+---------+
| 2005-09-01 00:00:00 |   10001 |
| 2005-09-12 00:00:00 |   10003 |
| 2005-09-30 00:00:00 |   10004 |
+---------------------+---------+
3 rows in set (0.00 sec)

數值處理函數

第12章彙總數據

彙集函數

AVG()

mysql> select AVG(prod_price) as avg_price from products;
+-----------+
| avg_price |
+-----------+
| 16.133571 |
+-----------+
1 row in set (0.01 sec)

mysql> select AVG(prod_price) as avg_price from products where vend_id = '1003';
+-----------+
| avg_price |
+-----------+
| 13.212857 |
+-----------+
1 row in set (0.01 sec)

COUNT()

mysql> select COUNT(*) as num_cust from customers;
+----------+
| num_cust |
+----------+
|        5 |
+----------+
1 row in set (0.00 sec)

mysql> select COUNT(cust_email) as num_cust from customers;
+----------+
| num_cust |
+----------+
|        3 |
+----------+
1 row in set (0.00 sec)

MAX()

mysql> select MAX(prod_price) as max_price from products;
+-----------+
| max_price |
+-----------+
|     55.00 |
+-----------+
1 row in set (0.00 sec)

MIN()

mysql> select MIN(prod_price) as max_price from products;
+-----------+
| max_price |
+-----------+
|      2.50 |
+-----------+
1 row in set (0.00 sec)

SUM()

mysql> select SUM(quantity) as ieems_orders from orderitems where order_num = '20005';
+--------------+
| ieems_orders |
+--------------+
|           19 |
+--------------+
1 row in set (0.00 sec)

彙集不一樣值

以上5個彙集函數均可以以下使用：
對全部的行執行計算，指定ALL參數或不給參數（由於ALL是默認
行爲）；
只包含不一樣的值，指定DISTINCT參數。程序員

mysql> select AVG(distinct prod_price) as avg_price from products where vend_id = '1003';
+-----------+
| avg_price |
+-----------+
| 15.998000 |
+-----------+
1 row in set (0.00 sec)

組合彙集函數

mysql> select COUNT(*) as num_items, MIN(prod_price) as min_price, MAX(prod_price) as max_price, AVG(prod_price) as avg_price from products;
+-----------+-----------+-----------+-----------+
| num_items | min_price | max_price | avg_price |
+-----------+-----------+-----------+-----------+
|        14 |      2.50 |     55.00 | 16.133571 |
+-----------+-----------+-----------+-----------+
1 row in set (0.00 sec)

第13章分組數據

mysql> select vend_id, COUNT(*) as num_prods from products group by vend_id;
+---------+-----------+
| vend_id | num_prods |
+---------+-----------+
|    1001 |         3 |
|    1002 |         2 |
|    1003 |         7 |
|    1005 |         2 |
+---------+-----------+
4 rows in set (0.00 sec)

mysql> select vend_id, COUNT(*) as num_prods from products group by vend_id with rollup;
+---------+-----------+
| vend_id | num_prods |
+---------+-----------+
|    1001 |         3 |
|    1002 |         2 |
|    1003 |         7 |
|    1005 |         2 |
|    NULL |        14 |
+---------+-----------+
5 rows in set (0.00 sec)

在具體使用GROUP BY子句前，須要知道一些重要的規定。正則表達式

 GROUP BY子句能夠包含任意數目的列。這使得能對分組進行嵌套，sql

爲數據分組提供更細緻的控制。數據庫

 若是在GROUP BY子句中嵌套了分組，數據將在最後規定的分組上安全

進行彙總。換句話說，在創建分組時，指定的全部列都一塊兒計算app

（因此不能從個別的列取回數據）。less

 GROUP BY子句中列出的每一個列都必須是檢索列或有效的表達式ide

（但不能是彙集函數）。若是在SELECT中使用表達式，則必須在函數

GROUP BY子句中指定相同的表達式。不能使用別名。

 除彙集計算語句外， SELECT語句中的每一個列都必須在GROUP BY子

句中給出。

 若是分組列中具備NULL值，則NULL將做爲一個分組返回。若是列

中有多行NULL值，它們將分爲一組。

 GROUP BY子句必須出如今WHERE子句以後， ORDER BY子句以前。

過濾分組

mysql> select vend_id, COUNT(*) as num_prods from products group by vend_id having COUNT(*) >=3;
+---------+-----------+
| vend_id | num_prods |
+---------+-----------+
|    1001 |         3 |
|    1003 |         7 |
+---------+-----------+
2 rows in set (0.00 sec)

mysql> select vend_id, COUNT(*) as num_prods from products where prod_price >= 10 group by vend_id having COUNT(*) >=2; 
+---------+-----------+
| vend_id | num_prods |
+---------+-----------+
|    1003 |         4 |
|    1005 |         2 |
+---------+-----------+
2 rows in set (0.00 sec)

mysql> select order_num, SUM(quantity*item_price) as ordertotal
    -> from orderitems
    -> group by order_num
    -> having SUM(quantity*item_price) >= 50;
+-----------+------------+
| order_num | ordertotal |
+-----------+------------+
|     20005 |     149.87 |
|     20006 |      55.00 |
|     20007 |    1000.00 |
|     20008 |     125.00 |
+-----------+------------+
4 rows in set (0.00 sec)

mysql> select order_num, SUM(quantity*item_price) as ordertotal
    -> from orderitems
    -> group by order_num
    -> having SUM(quantity*item_price) >= 50
    -> order by ordertotal;
+-----------+------------+
| order_num | ordertotal |
+-----------+------------+
|     20006 |      55.00 |
|     20008 |     125.00 |
|     20005 |     149.87 |
|     20007 |    1000.00 |
+-----------+------------+
4 rows in set (0.00 sec)

select子句順序

第14章使用子查詢

利用子查詢進行過濾

mysql> select cust_id from orders where order_num in (select order_num from orderitems where prod_id = 'TNT2');
+---------+
| cust_id |
+---------+
|   10001 |
|   10004 |
+---------+
2 rows in set (0.00 sec)

mysql> select cust_id, cust_contact
    -> from customers
    -> where cust_id in (
    ->      select cust_id from orders where order_num in (
    ->              select order_num from orderitems where prod_id = 'TNT2'));
+---------+--------------+
| cust_id | cust_contact |
+---------+--------------+
|   10001 | Y Lee        |
|   10004 | Y Sam        |
+---------+--------------+
2 rows in set (0.00 sec)

(1) 從customers表中檢索客戶列表。

(2) 對於檢索出的每一個客戶，統計其在orders表中的訂單數目。

mysql> select cust_name,
    -> cust_state,
    -> (select COUNT(*)
    ->  from orders
    ->  where orders.cust_id = customers.cust_id) as orders
    -> from customers
    -> order by cust_name;
+----------------+------------+--------+
| cust_name      | cust_state | orders |
+----------------+------------+--------+
| Coyote Inc.    | MI         |      2 |
| E Fudd         | IL         |      1 |
| Mouse House    | OH         |      0 |
| Wascals        | IN         |      1 |
| Yosemite Place | AZ         |      1 |
+----------------+------------+--------+
5 rows in set (0.00 sec)

第15章聯結表

建立聯結

mysql> select vend_name, prod_id, prod_price
    -> from vendors, products
    -> where vendors.vend_id = products.vend_id
    -> order by vend_name, prod_name;
+-------------+---------+------------+
| vend_name   | prod_id | prod_price |
+-------------+---------+------------+
| ACME        | FB      |      10.00 |
| ACME        | FC      |       2.50 |
| ACME        | DTNTR   |      13.00 |
| ACME        | SAFE    |      50.00 |
| ACME        | SLING   |       4.49 |
| ACME        | TNT1    |       2.50 |
| ACME        | TNT2    |      10.00 |
| Anvils R Us | ANV01   |       5.99 |
| Anvils R Us | ANV02   |       9.99 |
| Anvils R Us | ANV03   |      14.99 |
| Jet Set     | JP1000  |      35.00 |
| Jet Set     | JP2000  |      55.00 |
| LT Supplies | FU1     |       3.42 |
| LT Supplies | OL1     |       8.99 |
+-------------+---------+------------+
14 rows in set (0.00 sec)

mysql> select vend_name, prod_id, prod_price
    -> from vendors inner join products
    -> on vendors.vend_id = products.vend_id
    -> order by vend_name, prod_name;
+-------------+---------+------------+
| vend_name   | prod_id | prod_price |
+-------------+---------+------------+
| ACME        | FB      |      10.00 |
| ACME        | FC      |       2.50 |
| ACME        | DTNTR   |      13.00 |
| ACME        | SAFE    |      50.00 |
| ACME        | SLING   |       4.49 |
| ACME        | TNT1    |       2.50 |
| ACME        | TNT2    |      10.00 |
| Anvils R Us | ANV01   |       5.99 |
| Anvils R Us | ANV02   |       9.99 |
| Anvils R Us | ANV03   |      14.99 |
| Jet Set     | JP1000  |      35.00 |
| Jet Set     | JP2000  |      55.00 |
| LT Supplies | FU1     |       3.42 |
| LT Supplies | OL1     |       8.99 |
+-------------+---------+------------+
14 rows in set (0.00 sec)

mysql> select cust_name, cust_contact
    -> from customers, orders, orderitems
    -> where customers.cust_id = orders.cust_id
    -> and orders.order_num = orderitems.order_num
    -> and prod_id = 'TNT2';
+----------------+--------------+
| cust_name      | cust_contact |
+----------------+--------------+
| Coyote Inc.    | Y Lee        |
| Yosemite Place | Y Sam        |
+----------------+--------------+
2 rows in set (0.00 sec)

第16章建立高級聯結

使用表別名

# 使用列別名
mysql> select Concat(RTrim(vend_name), ' (', RTrim(vend_country), ')') as
    -> vend_title
    -> from vendors
    -> order by vend_name;
+-------------------------+
| vend_title              |
+-------------------------+
| ACME (USA)              |
| Anvils R Us (USA)       |
| Furball Inc. (USA)      |
| Jet Set (England)       |
| Jouets Et Ours (France) |
| LT Supplies (USA)       |
+-------------------------+
6 rows in set (0.00 sec)

# 使用表別名
mysql> select cust_name, cust_contact
    -> from customers as c, orders as o, orderitems as oi
    -> where c.cust_id = o.cust_id
    -> and oi.order_num = o.order_num
    -> and prod_id = 'TNT2';
+----------------+--------------+
| cust_name      | cust_contact |
+----------------+--------------+
| Coyote Inc.    | Y Lee        |
| Yosemite Place | Y Sam        |
+----------------+--------------+
2 rows in set (0.00 sec)

使用不一樣的聯結

自聯結

假如你發現某物品（其ID爲DTNTR）存在問題，所以想知道生產該物

品的供應商生產的其餘物品是否也存在這些問題。此查詢要求首先找到

生產ID爲DTNTR的物品的供應商，而後找出這個供應商生產的其餘物品。

# 使用子查詢
mysql> select prod_id, prod_name
    -> from products
    -> where vend_id = (select vend_id
    ->                  from products
    ->                  where prod_id = 'DTNTR');
+---------+----------------+
| prod_id | prod_name      |
+---------+----------------+
| DTNTR   | Detonator      |
| FB      | Bird seed      |
| FC      | Carrots        |
| SAFE    | Safe           |
| SLING   | Sling          |
| TNT1    | TNT (1 stick)  |
| TNT2    | TNT (5 sticks) |
+---------+----------------+
7 rows in set (0.00 sec)

# 使用自聯結
mysql> select p1.prod_id, p1.prod_name
    -> from products as p1, products as p2
    -> where p1.vend_id = p2.vend_id
    -> and p2.prod_id = 'DTNTR';
+---------+----------------+
| prod_id | prod_name      |
+---------+----------------+
| DTNTR   | Detonator      |
| FB      | Bird seed      |
| FC      | Carrots        |
| SAFE    | Safe           |
| SLING   | Sling          |
| TNT1    | TNT (1 stick)  |
| TNT2    | TNT (5 sticks) |
+---------+----------------+
7 rows in set (0.00 sec)

天然聯結

mysql> select c.*, o.order_num, o.order_date, oi.prod_id, oi.quantity, oi.item_price
    -> from customers as c, orders as o, orderitems as oi
    -> where c.cust_id = o.cust_id
    -> and oi.order_num = o.order_num
    -> and oi.prod_id = 'FB';
+---------+-------------+----------------+-----------+------------+----------+--------------+--------------+-----------------+-----------+---------------------+---------+----------+------------+
| cust_id | cust_name   | cust_address   | cust_city | cust_state | cust_zip | cust_country | cust_contact | cust_email
     | order_num | order_date          | prod_id | quantity | item_price |
+---------+-------------+----------------+-----------+------------+----------+--------------+--------------+-----------------+-----------+---------------------+---------+----------+------------+
|   10001 | Coyote Inc. | 200 Maple Lane | Detroit   | MI         | 44444    | USA          | Y Lee        | ylee@coyote.com |     20005 | 2005-09-01 00:00:00 | FB      |        1 |      10.00 |
|   10001 | Coyote Inc. | 200 Maple Lane | Detroit   | MI         | 44444    | USA          | Y Lee        | ylee@coyote.com |     20009 | 2005-10-08 00:00:00 | FB      |        1 |      10.00 |
+---------+-------------+----------------+-----------+------------+----------+--------------+--------------+-----------------+-----------+---------------------+---------+----------+------------+
2 rows in set (0.00 sec)

外部聯結

# 內鏈接
# 檢索全部客戶及其訂單
mysql> select customers.cust_id, orders.order_num
    -> from customers inner join orders
    -> on customers.cust_id = orders.cust_id;
+---------+-----------+
| cust_id | order_num |
+---------+-----------+
|   10001 |     20005 |
|   10001 |     20009 |
|   10003 |     20006 |
|   10004 |     20007 |
|   10005 |     20008 |
+---------+-----------+
5 rows in set (0.00 sec)

# 外部聯結
# 包含那些沒有訂單的客戶
mysql> select customers.cust_id, orders.order_num
    -> from customers left outer join orders
    -> on customers.cust_id = orders.cust_id;
+---------+-----------+
| cust_id | order_num |
+---------+-----------+
|   10001 |     20005 |
|   10001 |     20009 |
|   10002 |      NULL |
|   10003 |     20006 |
|   10004 |     20007 |
|   10005 |     20008 |
+---------+-----------+
6 rows in set (0.00 sec)

使用帶彙集函數的聯結

# 檢索全部客戶及每一個客戶所下的訂單數
mysql> select customers.cust_name, customers.cust_id, COUNT(orders.order_num) as num_ord
    -> from customers inner join orders
    -> on customers.cust_id = orders.cust_id
    -> group by customers.cust_id;
+----------------+---------+---------+
| cust_name      | cust_id | num_ord |
+----------------+---------+---------+
| Coyote Inc.    |   10001 |       2 |
| Wascals        |   10003 |       1 |
| Yosemite Place |   10004 |       1 |
| E Fudd         |   10005 |       1 |
+----------------+---------+---------+
4 rows in set (0.00 sec)

# 包含沒有任何訂單的客戶
mysql> select customers.cust_name, customers.cust_id, COUNT(orders.order_num) as num_ord
    -> from customers left outer join orders
    -> on customers.cust_id = orders.cust_id
    -> group by customers.cust_id;
+----------------+---------+---------+
| cust_name      | cust_id | num_ord |
+----------------+---------+---------+
| Coyote Inc.    |   10001 |       2 |
| Mouse House    |   10002 |       0 |
| Wascals        |   10003 |       1 |
| Yosemite Place |   10004 |       1 |
| E Fudd         |   10005 |       1 |
+----------------+---------+---------+
5 rows in set (0.00 sec)

使用聯結和聯結的條件

在總結關於聯結的這兩章前，有必要彙總一下關於聯結及其使用的

某些要點。

 注意所使用的聯結類型。通常咱們使用內部聯結，但使用外部聯

結也是有效的。

 保證使用正確的聯結條件，不然將返回不正確的數據。

 應該老是提供聯結條件，不然會得出笛卡兒積。

 在一個聯結中能夠包含多個表，甚至對於每一個聯結能夠採用不一樣

的聯結類型。雖然這樣作是合法的，通常也頗有用，但應該在一

起測試它們前，分別測試每一個聯結。這將使故障排除更爲簡單。

第17章組合查詢

建立組合查詢

# where查詢
mysql> select vend_id, prod_id, prod_price
    -> from products
    -> where prod_price <= 5 or vend_id in (1001, 1002);
+---------+---------+------------+
| vend_id | prod_id | prod_price |
+---------+---------+------------+
|    1001 | ANV01   |       5.99 |
|    1001 | ANV02   |       9.99 |
|    1001 | ANV03   |      14.99 |
|    1003 | FC      |       2.50 |
|    1002 | FU1     |       3.42 |
|    1002 | OL1     |       8.99 |
|    1003 | SLING   |       4.49 |
|    1003 | TNT1    |       2.50 |
+---------+---------+------------+
8 rows in set (0.00 sec)

# union
mysql> select vend_id, prod_id, prod_price
    -> from products
    -> where prod_price <= 5
    -> union
    -> select vend_id, prod_id, prod_price
    -> from products
    -> where vend_id in (1001, 1002);
+---------+---------+------------+
| vend_id | prod_id | prod_price |
+---------+---------+------------+
|    1003 | FC      |       2.50 |
|    1002 | FU1     |       3.42 |
|    1003 | SLING   |       4.49 |
|    1003 | TNT1    |       2.50 |
|    1001 | ANV01   |       5.99 |
|    1001 | ANV02   |       9.99 |
|    1001 | ANV03   |      14.99 |
|    1002 | OL1     |       8.99 |
+---------+---------+------------+
8 rows in set (0.00 sec)

UNION與WHERE 本章開始時說過，UNION幾乎老是完成與多個

WHERE條件相同的工做。UNION ALL爲UNION的一種形式，它完成

WHERE子句完成不了的工做。若是確實須要每一個條件的匹配行全

部出現（包括重複行），則必須使用UNION ALL而不是WHERE。

# 排序union查詢
mysql> select vend_id, prod_id, prod_price
    -> from products
    -> where prod_price <= 5
    -> union
    -> select vend_id, prod_id, prod_price
    -> from products
    -> where vend_id in (1001, 1002)
    -> order by vend_id, prod_price;
+---------+---------+------------+
| vend_id | prod_id | prod_price |
+---------+---------+------------+
|    1001 | ANV01   |       5.99 |
|    1001 | ANV02   |       9.99 |
|    1001 | ANV03   |      14.99 |
|    1002 | FU1     |       3.42 |
|    1002 | OL1     |       8.99 |
|    1003 | FC      |       2.50 |
|    1003 | TNT1    |       2.50 |
|    1003 | SLING   |       4.49 |
+---------+---------+------------+
8 rows in set (0.00 sec)

第18章全文本搜索

使用全文本搜索

進行全文本搜索

mysql> select note_text
    -> from productnotes
    -> where Match(note_text) Against('rabbit');
+-----------------------------------------------------------------------------------------------------------------------+
| note_text
|
+-----------------------------------------------------------------------------------------------------------------------+
| Customer complaint: rabbit has been able to detect trap, food apparently less effective now.
|
| Quantity varies, sold by the sack load.
All guaranteed to be bright and orange, and suitable for use as rabbit bait. |
+-----------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

mysql> select note_text, Match(note_text) Against('rabbit') as rank
    -> from productnotes;

使用查詢擴展

# 未使用查詢擴展
mysql> select note_text
    -> from productnotes
    -> where Match(note_text) Against('anvils');
+----------------------------------------------------------------------------------------------------------------------------------------------------------+
| note_text
                                   |
+----------------------------------------------------------------------------------------------------------------------------------------------------------+
| Multiple customer returns, anvils failing to drop fast enough or falling backwards on purchaser. Recommend that customer considers using heavier anvils. |
+----------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

# 使用擴展
mysql> select note_text
    -> from productnotes
    -> where Match(note_text) Against('anvils' with query expansion);
+----------------------------------------------------------------------------------------------------------------------------------------------------------+
| note_text
                                   |
+----------------------------------------------------------------------------------------------------------------------------------------------------------+
| Multiple customer returns, anvils failing to drop fast enough or falling backwards on purchaser. Recommend that customer considers using heavier anvils. |
| Customer complaint:
Sticks not individually wrapped, too easy to mistakenly detonate all at once.
Recommend individual wrapping.                       |
| Customer complaint:
Not heavy enough to generate flying stars around head of victim. If being purchased for dropping, recommend ANV02 or ANV03 instead. |
| Please note that no returns will be accepted if safe opened using explosives.
                                   |
| Customer complaint: rabbit has been able to detect trap, food apparently less effective now.
                                   |
| Customer complaint:
Circular hole in safe floor can apparently be easily cut with handsaw.
            |
| Matches not included, recommend purchase of matches or detonator (item DTNTR).
                                   |
+----------------------------------------------------------------------------------------------------------------------------------------------------------+
7 rows in set (0.00 sec)

此次返回了7行。第一行包含詞anvils，所以等級最高。第二

行與anvils無關，但由於它包含第一行中的兩個詞（customer

和recommend），因此也被檢索出來。第3行也包含這兩個相同的詞，但它

們在文本中的位置更靠後且分開得更遠，所以也包含這一行，但等級爲

第三。第三行確實也沒有涉及anvils（按它們的產品名）。

第19章插入數據

插入完整的行

mysql> insert into customers 
values(null, 'Prp E. LaPew', '100 Main Street', 'Los Angeles', 'CA', '90046', 'USA',null, null);
Query OK, 1 row affected (0.06 sec)

insert更安全的寫法

mysql> insert into customers(cust_name,
    ->                          cust_address,
    ->                          cust_city,
    ->                          cust_state,
    ->                          cust_zip,
    ->                          cust_country,
    ->                          cust_contact,
    ->                          cust_email)
    ->                  values('Pep E. LaPew',
    ->                          '100 main street',
    ->                          'Los Angeles',
    ->                          'CA',
    ->                          '90046',
    ->                          'USA',
    ->                          null,
    ->                          null);
Query OK, 1 row affected (0.04 sec)

插入多個行

其中單條INSERT語句有多組值，每組值用一對圓括號括起來，

用逗號分隔。

插入檢索出的數據

insert select

第20章更新和刪除數據

更新數據

# id爲10005的顧客增長Email
mysql> update customers
    -> set cust_email = 'emler@fudd.com'
    -> where cust_id = '10005';
Query OK, 1 row affected (0.03 sec)
Rows matched: 1  Changed: 1  Warnings: 0

刪除數據

mysql> delete from customers
    -> where cust_id = '10006';
Query OK, 1 row affected (0.04 sec)

更快的刪除若是想從表中刪除全部行，不要使用DELETE。

可以使用TRUNCATE TABLE語句，它完成相同的工做，但速度更

快（TRUNCATE實際是刪除原來的表並從新建立一個表，而不

是逐行刪除表中的數據）。

下面是許多SQL程序員使用UPDATE或DELETE時所遵循的習慣。

 除非確實打算更新和刪除每一行，不然絕對不要使用不帶WHERE

子句的UPDATE或DELETE語句。

 保證每一個表都有主鍵（若是忘記這個內容，請參閱第15章），儘量

像WHERE子句那樣使用它（能夠指定各主鍵、多個值或值的範圍）。

 在對UPDATE或DELETE語句使用WHERE子句前，應該先用SELECT進

行測試，保證它過濾的是正確的記錄，以防編寫的WHERE子句不

正確。

 使用強制實施引用完整性的數據庫（關於這個內容，請參閱第15

章），這樣MySQL將不容許刪除具備與其餘表相關聯的數據的行。

第21章建立和操縱表

第22章使用視圖

利用視圖簡化複雜的聯結

mysql> create view productcustomers as
    -> select cust_name, cust_contact, prod_id
    -> from customers, orders, orderitems
    -> where customers.cust_id = orders.cust_id
    -> and orderitems.order_num = orders.order_num;
Query OK, 0 rows affected (0.03 sec)

mysql> select * from productcustomers;
+----------------+--------------+---------+
| cust_name      | cust_contact | prod_id |
+----------------+--------------+---------+
| Coyote Inc.    | Y Lee        | ANV01   |
| Coyote Inc.    | Y Lee        | ANV02   |
| Coyote Inc.    | Y Lee        | TNT2    |
| Coyote Inc.    | Y Lee        | FB      |
| Coyote Inc.    | Y Lee        | FB      |
| Coyote Inc.    | Y Lee        | OL1     |
| Coyote Inc.    | Y Lee        | SLING   |
| Coyote Inc.    | Y Lee        | ANV03   |
| Wascals        | Jim Jones    | JP2000  |
| Yosemite Place | Y Sam        | TNT2    |
| E Fudd         | E Fudd       | FC      |
+----------------+--------------+---------+
11 rows in set (0.00 sec)

用視圖從新格式化檢索出的數據

mysql> create view vendorlocations as
    -> select Concat(RTrim(vend_name), ' (', RTrim(vend_country), ')') as vend_title
    -> from vendors
    -> order by vend_name;
Query OK, 0 rows affected (0.03 sec)

mysql> select * from vendorlocations;
+-------------------------+
| vend_title              |
+-------------------------+
| ACME (USA)              |
| Anvils R Us (USA)       |
| Furball Inc. (USA)      |
| Jet Set (England)       |
| Jouets Et Ours (France) |
| LT Supplies (USA)       |
+-------------------------+
6 rows in set (0.00 sec)

用視圖過濾不想要的數據

mysql> create view customeremaillist as
    -> select cust_id, cust_name, cust_email
    -> from customers
    -> where cust_email is not null;
Query OK, 0 rows affected (0.03 sec)

mysql> select * from customeremaillist;
+---------+----------------+---------------------+
| cust_id | cust_name      | cust_email          |
+---------+----------------+---------------------+
|   10001 | Coyote Inc.    | ylee@coyote.com     |
|   10003 | Wascals        | rabbit@wascally.com |
|   10004 | Yosemite Place | sam@yosemite.com    |
|   10005 | E Fudd         | emler@fudd.com      |
+---------+----------------+---------------------+
4 rows in set (0.00 sec)

使用視圖與計算字段

mysql> create view orderitemsexpanded as
    -> select order_num, prod_id, quantity, item_price, quantity*item_price as expanded_price
    -> from orderitems;
Query OK, 0 rows affected (0.02 sec)

mysql> select * from orderitemsexpanded
    -> where order_num = '20005';
+-----------+---------+----------+------------+----------------+
| order_num | prod_id | quantity | item_price | expanded_price |
+-----------+---------+----------+------------+----------------+
|     20005 | ANV01   |       10 |       5.99 |          59.90 |
|     20005 | ANV02   |        3 |       9.99 |          29.97 |
|     20005 | TNT2    |        5 |      10.00 |          50.00 |
|     20005 | FB      |        1 |      10.00 |          10.00 |
+-----------+---------+----------+------------+----------------+
4 rows in set (0.00 sec)

第23章使用存儲過程

建立存儲過程

# 在客戶端執行切換分隔符
mysql> delimiter //
mysql> create procedure productpricing(
    ->                                  out pl decimal(8,2),
    ->                                  out ph decimal(8,2),
    ->                                  out pa decimal(8,2))
    -> begin
    ->  select Min(prod_price)
    ->  into pl
    ->  from products;
    ->  select Max(prod_price)
    ->  into ph
    ->  from products;
    ->  select Avg(prod_price)
    ->  into pa
    ->  from products;
    -> end//
Query OK, 0 rows affected (0.00 sec)

mysql> delimiter ;

mysql> call productpricing(@pricelow, @pricehigh, @priceavg);
Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> select @pricelow, @pricehigh, @priceavg;
+-----------+------------+-----------+
| @pricelow | @pricehigh | @priceavg |
+-----------+------------+-----------+
|      2.50 |      55.00 |     16.13 |
+-----------+------------+-----------+
1 row in set (0.00 sec)

第24章使用遊標

第25章使用觸發器

建立觸發器

mysql> create trigger newproduct after insert on products
    -> for each row select 'Product added' into @ee;
Query OK, 0 rows affected (0.06 sec)

mysql> select @ee;
+------+
| @ee  |
+------+
| NULL |
+------+
1 row in set (0.00 sec)

mysql> desc products;
+------------+--------------+------+-----+---------+-------+
| Field      | Type         | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| prod_id    | char(10)     | NO   | PRI | NULL    |       |
| vend_id    | int(11)      | NO   | MUL | NULL    |       |
| prod_name  | char(255)    | NO   |     | NULL    |       |
| prod_price | decimal(8,2) | NO   |     | NULL    |       |
| prod_desc  | text         | YES  |     | NULL    |       |
+------------+--------------+------+-----+---------+-------+
5 rows in set (0.01 sec)

mysql> insert products(prod_id, vend_id, prod_name, prod_price)
    ->                                  values('20009', '1002', 'ysxu', 2.56);
Query OK, 1 row affected (0.04 sec)

mysql> select @ee;
+---------------+
| @ee           |
+---------------+
| Product added |
+---------------+
1 row in set (0.00 sec)

第26章管理事務處理

第28章安全管理

管理用戶

建立用戶帳號

create user [用戶名] identified by [用戶密碼]

用戶重命名

rename user [舊用戶名] to [新用戶名]

刪除用戶帳號

drop user [用戶名]

設置訪問權限

# 查看用戶的權限
show grants for [用戶名] //完整用戶名：'用戶名'@'主機'

# 設置訪問權限
grant all on *.* to [用戶名]
all-全部權限
*.*-全部數據庫下全部表

#grant的反操做是revoke

更改密碼

set password for [用戶名] = Password('密碼')
# 設置當前用戶的密碼
set password = Passwprd('密碼')

相關標籤/搜索

每日一句

每一个你不满意的现在，都有一个你没有努力的曾经。

MySQL基礎

第3章 使用MySQL

入門命令

第4章 檢索數據

檢索單列

檢索多列

檢索全部列

檢索不一樣的行

限制結果

第5章 排序檢索

排序數據

按多個列排序

指定排序方向

order by 和 limit 組合使用

第6章 過濾數據

檢查單個值

不匹配檢查

範圍值檢查

空值檢查

第7章 數據過濾

組合where子句

and操做符

or操做符

計算次序

in操做符

not操做符

第8章 使用通配符進行過濾

%通配符

_通配符

第9章 用正則表達式進行搜索

基本字符匹配

進行OR匹配

匹配幾個字符之一

匹配範圍

匹配特殊字符

匹配多個實例

定位符

第10章 建立可計算字段

拼接字段

使用別名

執行算數計算

第11章 使用數據處理函數

文本處理函數

日期和時間處理函數

數值處理函數

第12章 彙總數據

彙集函數

AVG()

COUNT()

MAX()

MIN()

SUM()

彙集不一樣值

組合彙集函數

第13章 分組數據

過濾分組

select子句順序

第14章 使用子查詢

利用子查詢進行過濾

第15章 聯結表

建立聯結

第16章 建立高級聯結

使用表別名

使用不一樣的聯結

自聯結

天然聯結

外部聯結

使用帶彙集函數的聯結

使用聯結和聯結的條件

第17章 組合查詢

建立組合查詢

第18章 全文本搜索

使用全文本搜索

進行全文本搜索

使用查詢擴展

第19章 插入數據

插入完整的行

insert更安全的寫法

插入多個行

插入檢索出的數據

第3章使用MySQL

第4章檢索數據

第5章排序檢索

第6章過濾數據

第7章數據過濾

第8章使用通配符進行過濾

第9章用正則表達式進行搜索

第10章建立可計算字段

第11章使用數據處理函數

第12章彙總數據

第13章分組數據

第14章使用子查詢

第15章聯結表

第16章建立高級聯結

第17章組合查詢

第18章全文本搜索

第19章插入數據

第20章更新和刪除數據

第21章建立和操縱表

第22章使用視圖

第23章使用存儲過程

第24章使用遊標

第25章使用觸發器

第26章管理事務處理

第28章安全管理