Share example code for operating MySQL views under Linux commands-Mysql Tutorial-php.cn

Share example code for operating MySQL views under Linux commands

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Release： 2017-05-10 15:57:20

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ViewVIEW commandIntroduction:

VIEW view is the stored SELECT statement data

1. Create view command format:

Create

[or replace]

[ALGORITHM = {UNDEFINED | MERGE | 不是Temptable}]
    [DEFINER = {user | 当前用户 }]
    [SQL SECURITY {DEFINER | INVOKER}]
    VIEW view_name [（column_list）]
    AS select_statement
    [WITH [CASCADED | 本地]检查选项]

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Format: CREATE VIEW view_name AS select_statement Create a view named view_name

View, view The content is the content from the selection statement query.

Usage:

CREATE VIEW sct AS SELECT名称，Cname，Tname FROM学生，课程，教师WHERE
student.CID1 = courses.CID AND courses.CID = teachers.TID;

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Store the queried data with equal CID in the student, course, and teacher tables in the SCT view.

2. Command function:

Store the selected data of the database as a view. The view is also equivalent to a virtual table. The table in the SELECT statement stored in the view is called the base table. The view cannot be modified and can only be modified based on the base table. . Therefore, it is generally not recommended to create views in MySQL.

3. Command parameters:

DISTING unique, non-duplicate

SELECT [DISTINCT] * FROM tb_name WHERE qual
if
ication;

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Select unique and non-duplicate entries that meet the conditions from the tb_name table.

Example

1. Check how the created table is created;

mysql> SHOW CREATE TABLE class \ G;
*************************** 1.行******************** *******

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Table: Class

创建表：CREATE TABLE`class`（
  `ID` int（11）NOT NULL AUTO_INCREMENT，
  `Name` char（20）NOT NULL，
  `Age` tinyint（4）NOT NULL，
  `Gender` varchar（10）NOT NULL，
  PRIMARY KEY（`ID`）
）ENGINE = InnoDB AUTO_INCREMENT = 5 DEFAULT CHARSET = gbk
1排（0.00秒）

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Error:

Unspecified query

5. Directly use the MySQL client without logging in to modify the data in mysql database

[root @ lamp〜]＃mysql -e'CREATE DATABASE edb;' 直接建立数据库EDB
[root @ lamp〜]＃mysql -e'SHOW DATABASES;'
+ -------------------- +
| 数据库|
+ -------------------- +
| information_schema |
| edb |
| hellodb |
| mydb |
| mysql |
| performance_schema |
| 学生|
| 测试|
| testdb |
+ -------------------- +
[root @ lamp〜]＃mysql -e'DROP DATABASE edb;' 直接删除EDB数据库
[root @ lamp〜]＃mysql -e'SHOW DATABASES;'       
+ -------------------- +
| 数据库|
+ -------------------- +
| information_schema |
| hellodb |
| mydb |
| mysql |
| performance_schema |
| 学生|
| 测试|
| testdb |
+ -------------------- +
[root @ lamp〜]＃mysql -e'SELECT * FROM students.class;'＃不登录mysql客户端，直接查询学生数据库中类表中的数据。
+ ---- + ------------- + ----- + -------- +
| ID | 名称| 年龄| 性别|
+ ---- + ------------- + ----- + -------- +
| 1 | 杨国| 22 | |
| 2 | 郭静| 46 | |
| 3 | 肖龙妮| 18 | |
| 4 | 黄荣| 40 | |
+ ---- + ------------- + ----- + -------- +

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